The only reason I can think of to get the Marantz slim line is for it's form factor. Ventilation for an avr is important, tho so might even consider adding a fan or something....
It isn't that the speaker has a nominal power rating, it may have a max continuous or program power rating and it may have a peak rating but they're generally more about melting points than anything particularly useful. You can use
this spl calculator to help estimate your amp needs for your speakers.
I wouldn't worry about the power of the amp particularly, unless you're just prone to drunken sessions where you turn the volume up all the way and can't tell that it's sounding like crap. Just use the volume control judiciously and you'll be fine...turn it down if it sounds bad.
Generally avrs have discrete amps but share a common power supply. All channels driven rating for surround content isn't all that important. Each channel at a given moment has the potential of it's rating per channel, and that isn't a real world scenario really; now if the same exact demand at the same moment is in all channels that may be a case for worrying about it....if you are worried about amp power get an avr with pre-outs for some flexibility.
The manuals for the gear would show you the location of IR reception point(s). I'd use wifi over bluetooth so wouldn't worry about what BT version its running, altho the better option might be nice if you must use bluetooth.
Try this for your Minimus 7s
https://www.hifiengine.com/manual_library/realistic/minimus-7.shtml