I recently read here that the ONLY 3 incompatible combinations are:
Keldorn/Viconia
Minsc/Edwin
Korgan/Aerie
--any other combos of good/evil should be stable, though you may get some nasty-looking squabbling within your party (actually it's entertaining
)
I've also heard something about Keldorn & Anomen having SERIOUS trouble with each other in a certain situation? - maybe someone else can expound on that, but it may be a SPOILER...
--- Sure, 3 mages are great, but whatever you do, don't skimp on your cleric. I never thought clerics were as important as mages until I had to deal with Undead creatures, which you will encounter in large quantities, as you will see. Most players prefer to have a "full" cleric (ie, not a multi-class, which will level up a lot slower) in their party - either Viconia or Anomen, depending on your taste (unless you play a cleric yourself, of course). Aerie's just fine, but I don't know if you can manage very well with her as your ONLY cleric... Best of luck!