With speakers like that. I'd go with nothing more than the ZX200.4
It's about 35W RMS per channel. And those speakers are about 30W RMS. They are more of a factory replacement rather than an amplified speaker. But if you don't wanna switch out your speakers again, that amp should push the to the best of the speakers possibilities. Just turn your gains down just a little, but I wouldn't worry about over powering them by 5W.
NO! It doesn't work that way. You need a channel per speaker.
Fronts (2 channels)
Rears (2 channels, optional for some people)
Sub(s) (1 channel)
Have you bought any of this gear yet? Cause if you only wanna use one amp, you could get a good 4 channel and bridge the rear channels for the sub, but you're probably not gonna get 750W or even close to it. Or you can try to find a 5 channel amp which usually has a little bigger 5th channel for the subs. But the best way is to get multiple amps for your multiple needs. Just back sure you have large enough wiring supplying the power back to a fused distro block.