We have the DB8 or DB8e, no DB8"B", though.
Fox is going to probably be the one network that's not easily (if at all) received. Despite the simulator's calculations, a 12 kW UHF signal from 55 miles away over hills is going to be a long shot. KQFX is on the same tower as KMIZ.
Yes, use a pre-amp. It will improve your system noise margin.
Electric lines typically cause problems on weak VHF (KOMU, for example). Only way to fix is to increase distance, should that be a problem.
I doubt you'll need the rotor unless you end up with a problem with multipath which is common in valleys.
We're located out in Ellisville not far from Manchester and just off Old State, so our office likely isn't too far away.