[Sephiroth]

With regard to Q2, what you want to do with the SH, keeping it in hub mode, is perfectly respectable. The Belkin router should be placed in the DMZ of the SH so as to minimise the work the SH has to do in routing to the Belkin. That's not essential, though. The Belkin may need to be placed into Bridge Mode.

With regard to Q1, you need RG6 coaxial cable. Make sure the ends are professionally fitted (Coaxial Male F connector). If done DIY and you're not sufficiently careful, the cable will pick up all sorts of RF noise and ruin it all.