The ceramic I think stays cooler than regular pads and they don't leave dust all over your wheels and I think they won't groove you rotors and they stop better as well. so I'm told. I got my pads from autozone and they don't have ceramic pads for the back
and it shouldn't mater what you have front or back as long as they match across from each other. The front is where you wont the ceramics anyway it does something like 70% of the braking.
My calipers I got at autozone they where $30 a peace but you have to take them your old ones as a core if not is $27 more per caliper. My calipers where fine I was worried about the back ones when i was looking at them cus the rubber looks really old but they should be fine and the front ones well they where so cheap I couldn't pass up the rears where $100 each cus they screw out and have the park brake stuff. Oh and my caliper that I got say toyota on them but the boxes say FENCO on them. I think that company just rebuilds them.