Looking into new rear channel speakers and have some general questions about placement and models

I am looking into Fluance AVBP2, Fluance XLBP, and Klipsch R14S for rear channel speakers to replace the ones I have now (Energy Connoisseur cb-5).

Currently, the Energy speakers are mounted on the wall via a bracket from Monoprice. They are mounted a bit higher than they should be (4-5ft above the ear/listening position), however, the bracket I purchased allows me to angle the speakers down a little to help with the height.

1. Do I need to be concerned about the height with any of those speakers listed above?

2. The rear right channel speaker is near the corner of the room, will that be a problem given that all three pairs of speakers listed above have two sides to them? Will that cause sounds to be thrown in a weird way, or will Audyssey compensate for that when I re-calibrate (Denon AVR-X3300W)?

3. With regards to the Fluance models I listed, the buying guide on this sub mentions the AVBP2 are better for smaller rooms, and the XLBP are better for larger rooms. What kind of sizes are we talking here? I can take some measurements of the space, but just wanted some ball park idea (especially if there was a definitive cutoff).

Any other feedback is welcome/appreciated :)