[Neomi]

Either Minsc or Valygar, suitably equipped and buffed, will make a great tank. As others have stated, Minsc maybe has an advantage in terms of brute force/tanking ability (can use Lilacor early on, or double wield axes/flails later), Valygar slightly better at stealth and useful for backstabbing (also consider that he can double-wield some of the very nice Katanas in the game).

My suggestion, as always, is to try a new combination of characters. Whether they get along (and what banter you'll get) is all part of the fun.

In terms of role-playing, I'm not sure I understand the Edwin/Viconia choice for a LG Inquisitor. Edwin is precisely the type of mage that you are supposedly in opposition to. Viconia is fine if your long term plan is to romance her and perhaps convince her to take a new path. However, Edwin is utterly evil and unredeemable. No matter how good a mage he is. Just take Imoen and Jan and leave Edwin somewhere in the depths of Spellhold.