I'll bite on a chunk or two of this...
WROC is predicted to arrive at your location at a NM of -20.2 via a tropospheric path. WSEE is worse, -31.3 dB NM and a tropospheric path. That you have seen any hint of them so far is false encouragement, the weak signal levels (which are sure to vary widely due to the over the horizon path) plus the co-channel and adjacent channel interference all will prevent reliable reception. To improve the situation would require a taller tower... much much taller. You can re-run your TVFR at up to 500' if you're curious, but I doubt 500' would be much of an improvement.
Enormous commercial grade antennas with gain figures in the mid 20 dB range exist. But I would expect the effect of fading and interference to be greater than that gain.
http://www.wade-antenna.com/Wade/uhfparabolic.pdf
Take a look at this idea...
http://forum.tvfool.com/showthread.php?t=820
I don't expect it to be a perfect fit for you, but in light of the dismal outlook for WROC and WSEE, would you want to pursue ideas like it?
Mixing signals from multiple antennas is done by the cable company by receiving the signal off the air, 'stripping the RF' and then using the analog or digital video and audio to modulate a new RF carrier produced in their equipment. You would be looking at $1000 or more per RF channel to do this yourself.
As a matter of practicality, would you consider two or three separate antenna systems and a distribution system that let you send feed 'A' to some outlets and feed 'B' or 'C' to other outlets? A main family room with need for all of the antenna feeds would be wired with a feed from all the antennas and an A/B/C switch would select the desired feed.
http://www.mcmelectronics.com/produc...-1490-/33-1490
I would ask the tower vendor about the capacity of the tower. I have no business guessing about the tower capacity or how it's installation may affect it's rating.