Can we use AVB for RM stage snake and Firewire FOH to desktop for Plug-in (multirack?)

I've attempted to call a couple of times and been on hold for no less than 40 minutes each time. My church is wanting to use our 32AI board FOH and the RM32 for stage snake which currently were not having any issues. We've merged to in-ears and now would like the option to use waves multirack foh for our live processing. The issue I for see is that to use the rRM32 as the stagebox you have to tell the chael its communication to FOH via Ethernet but then you cant send a chael via firewire to a computer as well? is it truly and either/or situation? what am I missing?

Secondly if we don't use multirack and use studio one, can you only return from the daw to as many "free" chaels on the board you have? ie. 6 vocals go into studio one and are all processed differently, I would need 6 open chaels on our board to return them to?

fingers crossed I can get an answer or two. were not a large church with a big budget so we'd like to not have to change our gear to get the features were looking for.

Thank You!