Thanks for the feedback. Yes, unfortunately, I'm stuck placing the TV above the fireplace -- and acknowledge it's a compromised setup. Fortunately, there is another room in the house that permits a proper floor/front standing speaker arrangement.

For this 5.1 placement, I referenced the HTR 7000 Owner's Manual -- I'm strongly considering the placement as shown in the attached image (see highlighted yellow) -- using HTR 7000s all around. Or would the placement of the rear speakers be better to the immediate left/right of the center listening area (there isn't much room)? Thoughts?

(Note -- Dolby Atmos is not a requirement / concern)

The rear corner placement highlighted is a good choice.