Donny, with the setup I used, I had more than enough inputs on the Compact, one for the keyboard, one for the laptop's audio output, plus a stereo RCA input, and a separate mic input for folks that needed to make announcements. My mic went directly into the TC Harmony-M, which outputted to the keyboard's line in. I never had a guest singer - and to be realistic, I didn't want one either. If someone showed up with a guitar and wanted to set in, which never happened in all those years, I would have anticipated that they had their own system.
Now, I have friends, just like you, that run everything through a mixer. After closely looking at my setup, two of them dumped their mixers and set up the same way I did. To me, a mixer was just one more unnecessary piece of gear that added lots more cables, and added one more item to the mix that could easily fail because of the wiring complexity. As you and most others are well aware, the more cables in the system, the higher the overall system failure rate.
Good Luck, and enjoy that new keyboard,
Gary