Hi Alson, Welcome
!!!
First off, great looking party! Everyone will be able to haul their own weight it looks like.
One issue: the halfling. If I were you I wouldn't worry about thieving skills. With a small party like you've got you won't lack skill points, and as you progress towards the end of your adventure you'll have way too many to care about. So my advice would be to go for a half-orc Fighter/Thief with 19 Str, 18 Dex and 19 Con. You'll be able to hold your own in early fights far better than a halfling with his puny little 17 Str. On the other hand, your halfling would make a killer ranged attacker. Consider Short Bows and Tasheron's Bow +3 in particular.
Fighter/Illusionist: kick ASS! Same with the Sorcerer and Ranger/Cleric. You are in for a very fun game
-- Nifft