Sure thing!
Upgrading to 5.1.4 sounds great! With your existing setup, adding Atmos speakers is a smart move. The Motion 2i's you found for $170 are a good deal and should blend well with your current system. If considering the 4i's for more depth, they'd be better upfront, while the 2i's can...
The MartinLogan centers, "ElectroMotion ESL C" and "Motion 30," are magnetically shielded, so they shouldn't mess with your CRT TV. Sorry you had trouble reaching MartinLogan support. For tech support, try [email protected].
Your 7.2.4 setup sounds absolutely incredible, and it seems like you've chosen some top-notch components. The McIntosh and Marantz amps paired with those ML speakers must make for a truly immersive experience. And I must say, that Epson 4K projector coupled with the Stewart Firehawk screen must...
Ah, the good ol' resonant bass buzz issue. It's a pesky problem, especially with vintage gear like your Sequel IIs. Since you've already inspected the caps and components, you might want to try a modern damping solution.
A popular choice is acoustic foam or damping mats, easily found online or...