Man that's gonna drive the OCD guys wild! It would drive me a little bonkers to not have the speakers framing the display, too, tho. Fireplaces can be nice, but don't mix well with TVs (or audio gear) sometimes. I'd try to get all the speakers to surround the display better, not just the L/R but also surrounds, but that's me. Ear level is my preference as well for the fronts, surrounds I could live with up near the ceiling, tho.
What are the current speakers? What are the speakers you're considering? They have built in presence speakers? Not familiar with anything like that I can think of. Bounce off the ceiling type or ?