GnomeWorks said:And will they be as mechanically fleshed-out as the ones in the PH?
They will be adequate for your needs.
So if I want monsters to have uses outside of combat, I need to do all the work? As if I didn't have enough on my plate already. Yes, I realize that the majority of the fluff in 3.5 was ignored (hell, I ignored it a good deal of the time), but it was useful as a springboard for my own ideas.
No, if you want monsters to have uses outside of combat, all the work is done for you. "Once every 99 years, a pit fiend can grant a mortal's wish". That's no different to 3.5's "Once every year, a pit fiend can grant a mortal's wish".