How best to arrange cables in this room...

While I don't disagree with what you say, I worry about loops of cable are the basic inductor shown in any electrical physics book.   It is a small inductor, but it is an inductor.

Coiling wire increases inductance, but coiling cable doesn't, since both wires in the cable produce magnetic flux in opposite directions.  That is how non-inductive resistors are woven (bifilar resistors).  It is also principle of common mode choke with inductance for common mode signals and zero inductance for normal mode (differential) signals.  In addition most of speaker cables' wires are twisted (would be stupid not to) and twisting greatly reduces cable's magnetic field for wavelengths much longer than twist pitch (wavelength at 20kHz is 10km).

As for uneven cables - if you believe that speaker cable affects the sound it will be proportional to length.  If it is inaudible to you, then the only think to consider is how hard would it be to sell them in the future.

@ghdprentice this is true. one of the amp options I am looking at are triode labs americano 45 mono blocks, which are pretty small form factor each and could possibly work placed near the speakers. A lot easier to hide interconnects vs speaker cables. Still deciding on whether I want to stick with integrated or go the monoblock route though, but that's a conversation for a different thread 😂

@kijanki Great point about future re-sale. Would be near impossible to sell varied length speaker cables.

If you go with monoblocks and longer interconnects I'd make sure to use balanced cables, preferably a star quad setup for noise rejection.

I had the same issue in a previous house and I drilled two small holes in the floor and ran the right speaker cable under the floor. The wall to wall carpet hid the holes when I moved.

All the best.