mixing brands
 

Ok I know it sounds dumb but is it a bad idea? I would like to get rid of my rear 4" blocks and found a good deal on a pair of rear springs but they are a different brand than the springs I put in front.

Irrelevant. I have unknown aftermarket front springs and stock rear springs with a shackle flip and they work great. There are so many variations of applications for springs they would never be the same from truck to truck. When you order a set of springs for a 3/4 ton 4x4 from one manufacture they are all the same but you may never haul stuff, someone else may have two extra tanks and a tool box and haul dirt all the time; no bumper vs my 150lb bumper; wood bed vs metal bed. It's all trial and error, even if you have a matched set.

I have 6" Rough Country EZ Rides up front and SkyJacker 5.5" SoftRides out back, no complaints here.

I don't even no where to begin with all my mismatches. Works fine for me. I've got: Skyjacker, Rough Country, Tuff country, Explore Pro Comp, Rugged Trail, to name a few.