I'm guessing that the balance will be really of if you get all the henchmen at the same time.
"Go squad! Protect your master!"

See, it'd be like that if I weren't a Paladin, and therefore also in the front lines with them.

This just feels like a normal adventurer party.

So I've confirmed, the mod doesn't work. I hired 2 different henchmen, and the second just replaced the first, who gets left exactly where they are until I hire them again.

I literally pressed "New post", how did that post get edited

That mod's pretty old and is probably no longer compatible with the latest version, hence why it doesn't work. I remember trying to do something similar a couple years back and hitting a similar wall, so you might just have to bite the bullet and do it normally.

If it helps, playing spellcasters can sorta give you a more comprehensive "party" through allowing you the addition of a summoned familiar/animal companion as well as a summoned monster. (They do take a portion of your XP though.) Honestly though, the biggest drawback to having a large party in the NWN games is that you'll run into all kinds of pathing and bodyblocking issues because most of the game was not designed for having more than 2 or 3 people following you into teeny tiny rooms. XD