I've been a player in a 6-month CtL campaign, and I'm currently co-DMing one, so, as you can see, there are plenty of possibilities to use CtL in a campaign setting.
I'll try to adress your various points one by one (although maybe not necessarly in order) :
- How to link the characters :
- A first good method is to have them be of the same court, or the same two courts. This way, you have a starting point to tie some of your characters together, and to introduce court-related plot points. Having some cours where your characters are not is also important : this way, there are things that your players don't know, and that is really important for you, as it allows you to use these other courts to scheme the way you want. If one of your characters don't want to be in one of the courts you need, you can have him be from a foreign court (eg : in a setting using the Seasonal Courts, have him be a Chinese businessman from the North Court, trying to implant a branch of its company here), or even be Courtless.
- Furthermore, remember the motley mechanic is here to help you. I'll address some good campaign starters in following points, but as soon as you sense you have a group dynamic, you can try to orient your players to form a motley, maybe even share a Hollow. If you make good use of pledges, they can simply be linked by a motley pledge, and have to follow the group because they swore to protect their friends.
- Threats to start a campaign with :
- You do not need your full meta-plot ready in the first sessions. In the campaigns I played (again, this is a purely empirical point of view, I do not affirm it's the best), the first scenario followed a simple rule : take some characters, put all of them in deep trouble, and watch how they have to form a group to get out of it. In the campaign I played, we found ourselves with a ODed changeling on our arms, and we had to find how to prove it wasn't our fault before his Summer friends come and break our knees in tiny little pieces. In the one I'm DMing, the players (without knowing each other before) all experienced the same nightmare (a bad trip from a Dream-Poisoned human), and had to understand why they were all here, and who was this guy that seemed in all that pain.
- Campaign ideas :
- In the previous point, I showed you how you could start your campaign with a simple plot. From here, you just need to watch your players, and see what kind of meta-plot would be good for them. They directly go to their courts, and try to charm their ways out of it ? Make a political campaign, with intrigues interacting directly with their lives. In my first campaign, we started at one-mantle-dot in the court, and finished with one in our group as Autumn Queen. This is just an example, but you get the point : see what they want to do, and use it to choose where you want to go.
- Furthermore, as said in the Storytelling part of the core book, CtL is more or less a fairy tale. Yes, a sad one, a dark one, one made of darkness and broken dreams. But the thing to remember here is that the global plot may be one of the fairy tale : kill the traitor, save the girl, things like that. CtL provides plenty of possible enemies apart from the Faes : hobs, Loyalists, Privateers, Bridge-Burners, or maybe just crazy humans.
- Character development :
- What's great in CtL is that it's a game that allows you to combine the two : a meta-plot, with great enemies to fight and things to understand, and a deep RP environment to build your characters. I'll even say that the meta-plot is kind of second here : with all they've been through, for me, the main part of playing CtL is watching how the players try to regain their life back, or create a new one. It can be anything : for example, in the campaign I played, even if the meta-plot was that we were trying to destroy a fae-touched drug ring of Loyalists, my character, on his side, became a country-famed juggler, and created its own show, and even his own kind of art, influenced by Faerie magic. And, frankly, that was the thing that marked the most
To finish, I'd advise you to read the books (all of them, if you can), as they are full of good ideas.
(nota bene : I'm not an English native, so please excuse the eventual errors. And if you need any more info, feel free to ask :))
I've run several campaigns with huge casts of characters. The key element to managing them all is to know what they're doing in the background, and why.
Give your NPCs their own missions
For example, my first major campaign included six prominent groups of NPCs: the Walkers, the Wizards, the Guardian, a werewolf pack, and two parties of NPC adventurers of similar level to the group. The Walkers were insanely powerful, but had their hands full dealing with the world-breaking effects of the BBEG's plans. Instead of tagging along with the PCs, the Walkers would send the PCs on "little" missions they knew the party could handle, and then go deal with the bigger, scarier stuff themselves.
The werewolf pack was introduced early, but spent some time in the background recovering from the plot events that had brought them into the game. Later, I introduced one of the two parties of NPC adventurers. As the reach of the BBEG's plan became clear, the PCs realized they couldn't fight back on all fronts - they simply couldn't be in two or three or five places at once. So they called on the werewolves and the NPC party. Just as the Wardens had directed the PCs on missions they didn't have time to handle, the PCs now directed this party of NPCs to deal with parts of the BBEG's plans while the PCs took care of other parts simultaneously.
(As an aside, this gives you as the GM a chance to let your players pick what they're interested in. I would present multiple mission hooks to my players and they'd choose which to take on themselves, and which to send their NPC friends on. That helped me get a feel for what sorts of missions interested my players and tailor the encounters accordingly.)
Have your BBEG target the NPCs
In that same campaign, the Wizards offered help to the players where they could, but when I realized they were getting too useful, I had disaster strike their tower in the form of the BBEG. The Wizards suddenly had to focus on saving themselves and their young apprentices, as well as protecting the MacGuffin they held, and didn't have resources to spare to help the PCs.
Similarly, the Guardian was an incredibly strong being with potentially game-breaking powers - but the BBEG was actively hunting her and if she spent too much time in one place, or used her powers too much, the BBEG would find her and possibly kill her. So she spent most of the game on the run, influencing things and providing occasional help where necessary, but only when she could do so safely. The players couldn't just summon her at the drop of a hat, and she couldn't stick around very long even when she was there.
Add a twist
The last big group of NPCs in that campaign was my fun secret: up until about halfway through the game, the players thought this party was also working against the BBEG. Then they learned that this party was actually working for the bad guy. Suddenly, a powerful group which the PCs had thought was on their side became a resource for the BBEG instead. They were still plot-relevant, but I could have them vanish for large chunks of time as they worked toward the BBEG's plans. (If I recall correctly, the PCs even sent one of the other NPC groups after this group at one point, so a whole bunch of my NPCs were fighting each other off-screen and I didn't have to deal with any of them!)
Borrow TV and movie techniques
Your NPCs don't all have to be on-screen at the same time. Borrow pacing and scene staging from TV shows and movies, where secondary characters conveniently happen to approach the main character one at a time. Things like, one person gets a phone call and has to walk away just as another is running up to report in; or groups of NPCs are set up in different physical locations so the PCs have to move from place to place to talk to each group.
Your NPCs are people with their own goals
The key thing to remember is that your NPCs are all people with their own goals and dreams and plans. Not all of them will want to be around the PCs at all times. Even if everyone in the world is working together to fight the BBEG, individuals will have different ideas of how to go about it. They might get upset at the PCs' chosen approach and storm off to do their own thing, or they might suggest a flanking maneuver, or something else that's useful but which takes place off-screen. Don't bind your NPCs to your PCs - a realistic world full of characters includes those characters running off to do things their own way.
Something I've found that helps generally is to ask for a little more information during character creation. Specifically I ask for...
With Savage Worlds specifically, it also helps if they can tie some of these things into the Hindrances they've chosen for their characters. Also, the Curious, Loyal and Heroic Hindrances are a godsend for this type of thing, as it makes it really, really easy to embroil those characters in whatever adventure is going on.
If you make it clear to your players that this information is going to be used to work out plot arcs then it will be easier to get their buy-in to what you are doing. When you have all the responses, you can see if there are possible connections between characters. Maybe two of them have a common enemy for example. The more you can interconnect these things, the more cohesive the whole thing will be. Another thing that can help is to ask each character to have an established connection with at least one other PC.
Some specific information on running The Flood, which is a plot point campaign...
Make sure you always end the session with a rough idea of where your characters are planning to go next. This will allow you to read up on any related Savage Tales you want to run, and tweak/change things to maybe incorporate aspects of the characters backgrounds, Hindrances etc. Maybe one of the places they have to go to get the McGuffin just happens to be buried in an abandoned mine in the one town where the wanted gun-slinger can never go back to.....that kind of thing.
The plot point provides a reason for a group to stay together near the start of the campaign, and the way plot points are designed to work is that it gives you freedom to throw personalised stuff at the characters in the gaps between each main story development. This structure should help keep things more coherent, as there will always be an overarching goal that all characters are interested in relating to the thrust of the big-bad story developments.