Hi @fthompson251 , you said you’re doing dual stereo in-ceiling (why?) and you got a few rounds of advice before calling on folks to check their audiophile hats… after you shied away from small chip amps due to your wife not liking a shrill-sounding device? C’mon now, stop being the pot calling the kettles, hey? 😉
Many of those small stereo amps would probably work well enough running speakers in parallel, but HDMI ARC won’t be common on small stuff since the former’s designed primarily for multichannel HT and the size you want is more desktop hifi. I agree using a secondary remote for a stereo mini amp to control TV volume is not ideal.
I’d think the sound compromises of sticking a quad of large woofers in the ceiling would be considerably more problematic for your wife’s ears than any particular small chip amp. Those big drivers, depending in part on which you use, could wind up beaming some of your frequency range in a way you didn’t hear with the previous 3” drivers; could give rather different results than you expect, especially without a typical AVR’s inbuilt software.
miniDSP now has a unit with HDMI ARC-in, but many devices as that one still won’t address ATMOS (your Apple TV might handle that suitably upstream, though, so maybe not a prob for that TV). They also are not cheap.
Your priorities and constraints don’t seem to be very well-matched for this project. Take some time and read up on available devices more would be my main recommendation. Not sure what to say about in-ceiling 8” drivers, maybe I misread something. Very unconventional choice, so, interesting.