[RPG] the point of the PCs being awarded titles

Use your character's backgrounds to build intrinsic motivation for your players' characters.

If you're looking at the LMoP adventure, you hopefully have the pre-built characters handy. If you look at their backgrounds, you can see that for every character, there is some kind of intrinsic motivation built into their backgrounds for at least one of the elements of the adventure.

This provides the characters with clear motivation for why they should care about both the mission and the results of the mission.

You can do this in a custom setting in a couple of different ways. First, you could assign different background elements to your players, this may be a bit of a deal breaker for some players, but I've had good luck with it using a pre-built adventure and giving my players the option of which of 10 or so to select (Horde of the Dragon Queen provides 10 different optional background elements).

However, the best thing you can do is to pick up plot elements from your characters' backgrounds. Have them write a short paragraph or even just be super detailed when they are building their BIFT part of their background so that you can mine that for details and NPCs and other motivations.

If you're looking to provide intrinsic motivation, having it worked into your characters' backgrounds is the best and easiest way to do it.

Spoilers ahead:

The most information we can get from the book can be found in the General Features section of the hideout description, in the box titled "What the Redbrands know" (page 20):

The Redbrands have a handful of captives in a holding area "near the old crypts," which are guarded by skeletons (see areas 4 and 5).

This only tells us that the Redbrands are aware of the skeletons (it's their trap after all). However, it is likely that at least some of the Redbrands would know the command word as well, as the trap is positioned right in front of their prison, and the skeletons might otherwise interfere with prisoner transfer.

If this doesn't seem likely to you, there is at least one person in the hideout that is expected to know such things: Glasstaff himself. Though it is not strictly specified in the book, it is very likely that he's the one who set up the whole trap, and thus would know the codeword.

As for how could your PC-s find this out? Interrogation, persuasion, magical effects, and others. While getting information that you don't ask for in an interrogation seems unlikely, a particularly successful one could yield it. For instance, if your PC rolled an Intimidation check while interrogating and got a very high score, an NPC might be so scared that he starts spewing out everything he knows (possibly pissing his pants at the same time). Or a well worded Suggestion ("Lead us safely through the hideout") spell might prompt an NPC to divulge such secrets. It's even possible to make allies out of enemies, and an ally would be incentivized to keep his new friends safe from skeletons.

As a side note: the adventure book you're using is not a rulebook. It is merely a suggestion on how to play the adventure the way the author imagined it. DM's are allowed (and required, imho) to adapt the adventure according to how the campaign is going.

Sticking to the book is handy for new DM's that are still struggling with all their other responsibilities and don't want to add adaptive storytelling to the list. But the book was not meant to be a cook book, so there are naturally some holes in the text that the DM is required to fill in. This is also good practice, as modifying the initial script in reaction to PC's actions usually leads to a much more enjoyable campaign than just going by the book.

In short:

The PC's might not enter the skeleton room at all, at which point the keyword is irrelevant. It is also irrelevant in case the players stumble upon the room before gathering any information. But it's good for a DM to know it exists so he can throw it in at any point in the game where it would make the game more enjoyable (as a reward for a high roll, or even as a new plot point that enriches the original adventure).