Ok, I still haven't pushed the BUY button just yet.

The enemy of a good plan is the search for a perfect plan!
Sounds like my plan is to start with a C5 + FM trap + a high quality 2-way splitter, some quality QS RG-6, snap-n-seal connectors and hope for the best. Hopefully the C5 is wide enough to capture Ch 7 & 9, and if I'm real lucky most of the UHF channels I'm going after.
If not covering UHF well enough, fallback plan would be to add a dedicated UHF antenna (model TBD) using the diplexer.
Any objections, let me know in the next 2 hours. Otherwise, please stay quiet! (too late after I buy them!)