the-elder-scrolls-v-skyrim
I've observed followers use staffs that have spells from the Conjuration and Destruction schools of magic only. I am wondering if followers will also use staffs with spells from the other schools of magic or all of the special staffs.
Which staffs will be used by followers, when given to them? Or alternatively, which staffs will not be used by any follower, when given to them?
List of all staffs in Skyrim [UESP Wiki article].
So here's what I know you can do (name followed by the quest you should start but not complete):
People
Animals
Summons
which brings the total to you, nine people, two dogs, a horse, two dead thralls and four atronaches. That's 13 permanent and almost everywhere (excluding atronaches and the horse) and 18 potential. This seems pretty hypothetical and I haven't done it myself, so feel free to correct me.
Other
There's also supposedly a glitch (patch status unknown) where you can dismiss your follower, hire someone else, then immediately return to your follower and rehire him or her. I don't know if people use it with the Dark Brotherhood Initiate(s) for a reason or because it only works with them.
Also Odahviing.
Time for more Skyrim Science!
So while I don't have a full answer to your question just yet, I do have some preliminary results.
I've been peeking around in the Skyrim Creation kit, looking at the spell effects for the five spells you list above. For instance:
The highest level reanimate spell has a magnitude of 40.
This is similar to how the master level frenzy spell, Mayhem, is set up, though it's magnitude is 25. This becomes relevant as soon as we read the effect's description:
Creatures and people up to level 25 will attack anyone nearby for 60 seconds
We've documented the frenzy effect over here already, so I think we can safely assume that if Reanimate works similarly (and there's no real reason it shouldn't), the magnitude of the spell effect correlates precisely with the maximum level corpse that can be raised.
That gives us this list:
Raise Zombie - up to level 6 creatures
Reanimate Corpse - up to level 13 creatures
Revenant - up to level 21 creatures
Dread Zombie - up to level 30 creatures
Dead Thrall - up to level 40 creatures
Which gives us an obvious series for our curve.
Double-casting conjuration spells increases the duration, not the effect, so that won't help against higher level enemies, but the Necromage perk will.
As to what level are which creatures, the first thing to realize is that certain creatures (i.e., Dragons, Giants, and Dwemer Automatons) simply cannot be reanimated.
That said here's as good a list as I can manage. If you don't see an NPC on here, it's most likely because they can be found at multiple levels. Creatures are listed under the minimum required spell to reanimate them:
Raise Zombie (up to 6):
Reanimate Corpse (up to 13):
Revenant (up to 21):
Dread Zombie (up to 30):
Dead Thrall (up to 40):
Too Powerful to Raise
Best Answer
This is an interesting question. Because of this question, I started giving Lydia all sorts of staffs that I found in my current game. She is using paralysis staff with great enthusiasm on top of the conjuration staffs and destruction staffs, so we will add that to our list. I took away chain lightening staff from her because it's an Area of Effect spell staff and it damages me all the time when she uses it. I gave her a healing staff, but she hasn't used it, yet. I'll give her a fear staff when I find one.
[Edit] I made the test more complete by giving Lydia a whole bunch of staffs I do not remember her using before and going through a couple of caves and bandit camps.
Alteration
Conjuration:Banish
Conjure:Conjure
Conjuration:Reanimate
Conjuration: Soul Trap
Destruction: Yes
Illusion: No
Restoration: Restore Health
Restoration: Turn Undead (Not tested yet)