Do I have to release e-brake, for rear brake replace?
 

sorry for the dumb question, but it says in the manual, which never helps me anyway) to release the tension, can i get around that??

i might as well replace all brakes while the wheels are off for suspension.

Yes, parking brake must be in the off position to remove rear drums. If you have rear discs, it has to be off also, to remove caliper from rotor.