Perhaps I'm wrong, that wouldn't be a first, but I believe such a setup would require speakers with their own amp, so the 7125 would be pretty much eliminated, unless you wanted some wired and some wireless speakers.
What is a 12.4 system? Front mains and center, 2 height, 2 width, and 5 surrounds with 4 discrete subs
I'd think the big problrm there would be the prepro feeding the amp for the front 7 and wireles for the other 2 + .4