Ok. Well, as far as the minimum impedance is concerned, that will only be at certain frequencies, and likely nothing to be tooooo concerned with.
@PENG will be good to answer that better.
For speaker placement I was hoping the rack will make way for the center channel as obviously you don’t want gear in front of it. Lol Bigger thing is the back of the room. You can’t have IC surrounds and still have Atmos. If that were my room, I would use the current surrounds as top rears(although they’re kind of far apart), and install top fronts to match. Then find some book shelf speakers or IW speakers for surround duty.
Ah bugga. Good point. I wish i had been the first owner of the house so i could've ensured they didn't install them that way. I don't think it will be possible to install the focal IW speakers at the back as the wall cavity is only 9cm and from memory the focal 300 iwlcr6's require 9.8cm. Is there any mounting accessory that will allow me to have them sticking out the wall by 1cm? If not, i could always mount two bookshelf speakers on the wall or find different speakers for the surround(any suggestions?). Any recommendations in terms of the model for the bookshelf speakers? As for the two speakers being far apart for IC speakers. I don't mind doing a 5.1.4 setup. However, unless i actually took the speakers out of the ceiling, patched and painted it and moved them where they should be for IC speakers it wouldn't be the perfect angle for atmos. Will the angle matter? Or would it be okay if it was inline with the sketch i've just attached?