If the noise is comming from the front it is more than likly 1 of 2 things:
1)brakes have reached the squeal tab(also known as the indicater tab) - pretty much telling you you'll need front brakes soon
2) There is a little "guard" that rides right by the rotor on the bottom inside of the rotor. Not really visable with the wheel on. sometimes ice or somthing can bend it just enough to have it rub on the rotor.
What you did in the rear isn't going to cause any issues in the front. And lets face it. e-brakes are pretty much useless on auto cars. if you are in such a tight spot that you need it to stop the car, chances are you've hit whatever it was you were hoping to avoid before your foot gets halfway to the e-brake. most senarios go like this: ahh crap! hit brakes- brakes drop to the floor - crunch. see no time for e-brake. I live in upper michigan and most cables on 10 year old cars are seized from lack of use anyways.
