cjspencer1: Thank you! I have gone through 2 areas of Chapter 2 (the Caves and Neverwinter Woods) and got enough exp to get to level 10. Noticed that Tomi was wearing a different set of armor when I leveled up. Tried asking him more about himself, but the only dialogue option available is "what do you think we should do now?" and I can't ask him any more about Sammy. I loaded a previous save (before Tomi's armor changed) and found the dialogue option missing there as well. Went back to the barracks and had similar problems with Sharwyn, and I can't ask about her Bard lover anymore after the 2nd conversation. This isn't supposed to happen, is it?
The henchmen will upgrade their equipment when they reach certain levels. I think it gets up to +3 as they get near level 14.
I went hunting for the specifics, to make sure I'm not misleading you. Here's what I found, and it looks about right for what I remember. Fear not, there are no spoilers.
When it talks about adventuring with a henchman, that really means "listened to their story and gave them the trinket they want". I completed all the henchman quests without ever taking them out of the hub area; you can find their respective items while adventuring, then you just hand over the item when you're high enough level and you've heard enough of their story that they mention what they're looking for.
For example, in Chapter 1 Boddyknock (gnome sorcerer) wants the Leaven Bread Recipe. You can find it while adventuring, then give it to him when he talks about wanting it (if your level is high enough, you can listen to his tale all at once and immediately give him the recipe if you have it in your inventory). He'll give you his reward item and say something to the effect of "let's focus on your adventure now".
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Henchman quests In addition to supporting the PC during the adventure, the henchmen have stories about themselves and their history. Each henchman tells a different tale in each chapter, and each story culminates in the desire to obtain some item. Giving this item to the henchman (via dialog; the item cannot be manually handed to the henchman) results in a small reward including a personal gift from the henchman. This reward item is made more powerful with each quest completed for that henchman (and possession of the reward item is required to gain the quest in later chapters).
Each tale spun by a henchmen is broken into three pieces. The first piece will be told merely for being in the correct module, provided the player asks for it. Hearing the second and third pieces also requires that the PC have a minimum character level. In addition, the final piece in later chapters requires that the PC possess the reward item from the previous chapter. (The requirement to possess the reward item is described in the journal as "adventured enough with [henchman] in the past so that s/he considers you a friend".) Specifically, the level requirements are as follows.
Chapter one Part 2: level 5
Part 3: level 6
Chapter two Part 2: level 9
Part 3: level 10
Chapter three Part 2: level 14
Part 3: level 15
There are no henchman quests in chapter four, nor in the chapter epilogues. Furthermore, as with other quests, a henchman quest begun in one chapter cannot be completed in its epilogue. There are no restrictions on how many henchman quests a single PC may complete though, so it is possible to complete all six quests in each of the three chapters.
Players who wish to skip part of the quests for whatever reason can spawn the reward items with the console command dm_spawnitem. The ResRef of the reward items start with "nw_hen_", followed by a three-letter abbreviation of the henchman's name ("bod", "dae", "gri", "lin", "sha", or "gal") and the chapter number, and they end with "rw". So, for example, the reward item given by Tomi Undergallows in chapter 2 has a ResRef of "nw_hen_gal2rw".
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