Mono inputs? Outputs to inputs as fx loop?

The decision between whether to buy the mpc x or live may come down to this functionality for me. Can you use the l/r inputs on mpc live, or inputs 1,2-3,4 on the mpc x, as mono? I found documentation stating that you can set the various outputs as mono, but nothing regarding mono inputs. I plan on using 2 mono outputs, and ideally 2 mono inputs, as separate fx sends and returns for analog filter manipulation. Any problems or things to watch out for with this workflow? It’d be great if this functionality is available on the mpc live.

I have a live and frequently record only one of the inputs to get a mono track, which saves space. I am not sure that I've ever recorded both at the same time (on separate tracks) but I think you could by arming them both. You could also always record stereo then split the left and right out after