no to both questions...
you need to add a line-output converter to send signal to an amplifier. Some amps come with circutry so you can plug speaker wires driectly into the amp, (mine does) but the circuits are never as good as a a dedicated converter like soundgates. Soundgate makes some of the best in the industry.
I've sent my front speaker wires into the line output converter, then sent that signal to an amp (with an Equalizer in the middle)... it's a 4 channel amp with the four front speakers driven off the front channels of the amp, and the sub driven off the rear channels. The rear door and d-pillar speakers are still deck powered, which i don't like, but i'm tired of doing speaker stuff for now.
I put the amp under the passenger seat and put the jack under the back seats. Honestly, there's so much space actually inside the rear seats i thought about putting the amp or subs in there, but again... i wanted to get the project done.