I'm not familiar with the unit you have, but here's some information on "mixing" various signals on a single coax. I have 4 satellite receivers and an attic mounted antenna for off-air signals. I use the antenna whenever the satellite goes out. That way I still can receive all my local channels. Also, I have the output of all 4 satellite receivers modulated, so I can watch any receiver on any of my 8 TV sets.
i.e, receiver 1 also outputs on ch 55, receiver 2 outputs on ch 60, etc. I then take all 4 outputs and the attic antenna and feed them to a 5 way splitter, except I turn it around and make a combiner out of it. So, just feed what signals you have to the output side of a splitter, and the input, becomes the combined output. You can use a 2 way, 3 way, or what ever you need. And, the signals can be digital or analog, cable, UHF, VHF, etc. It doesn't matter.
Regarding switching between signals and rescanning...in the setup I described above, as all the signals are on one "pipe", there's no need to switch cables. Some devices require that you rescan to "memorize" the channels though. Others can switch between signal types with the press of a button. For example, I have a Viso TV that I switch between HDMI and Antenna to watch either my satellite receiver (HDMI) or the antenna (TV) in my case.
Hope this helps! Good Luck!