As far as squarebills I've got confidence in quite a few with the now discontinued Xcalibur XCS100 being my main producer. Other I like are Luck E Strike RC's, Storm Arashi's, Rapala fat 3's. For that mid depth, I like the Bomber Fat Free Guppie, and Fingerling. Rapala DT 4's, 6's, & 10's will do work as well. As far as colors go, try to cover your bases. Get 1 or two baitfish patterns, a few crawfish ones, and a few bright ones as well. Pick colors based on your local forage, and pick ones you like or think will work. If you have faith and confidence in a bait, you'll fish it harder and you'll be more inclined to give it a chance and stick with it.
Lipless crankbaits are great options too. I really like the Booyah version and the Cotton Cordell Super Spot/Hot Spot. Pick colors the same as other crankbaits.