So consider a powerline network adapter, or move the PC to a place you can run a cable.

Just use gigabit networking. You are looking ~4h/TB give or take depending on a few factors.

Yes. Always protect your investment against earthquakes by placing them in a place from which they can not easily fall.

Depends on the media. High motion live action is going to require a higher bit rate than low motion animation.

No.

No.

Yes.

Buy server, sell drives, steal underpants, profit!