I've not ridden with hydraulics. A couple of things: I find that cheap chinese eBay pads for my BB7s last about twice as long as Avid pads and seem to perform the same.

Cables freezing depends on your climate. The worst is climates where the temps go above and below freezing. If it stays above, no problem. If it stays well below freezing, also no problem since there's never any liquid water to get into the cables in the first place.

I replace cables very infrequently. My cheap bike (the only one I have) is pushing 9 years old at this point, and I've replaced the cables once. I probably didn't even need to do that one, they weren't rusty or anything, but I figured it had been 4 years and I probably should replace them.