Yes. Everything you are asking about should work like you think. Of course it comes down to routing it correctly in each console. It’s going to be a little confusing to keep track of everything, but it will work.
I’d recommend that you start out small. Try routing an single input from the stage box to the SQ5 and Avantis. Once that works as expected, route a single output from the Avantis to the stage box, etc. Once you have the basic “road blocks” down on how to route things, it will make routing everything else much easier.