Rhythm and Performance have the same damper but the Rhythm is made of 6xxx series aluminum and Performance is 7xxx which supposed to be more rigid.
1x12 GX (with NX cassette) vs 1x11 XT (with SLX cassette) - on an ebike, I would go for the XT every day over the GX Eagle. That rear mech is flimsy, the cage is long and sticks out more to the side than the XT shadow (I have both on two of my bikes). Also, the range difference between the 11-50 NX and the 11-46 SLX cassette is totally negligible on an ebike.
Guide RE vs XT 4 piston Ice-Tech - hands down XT for me. (I had Guide RE and RS but I replaced them with Shimano Saints (XT is pretty much the same).
The difference is 500€ and I don't know if it worth it. The fork is almost the same, there are differences between the shifting and the brakes but they are also a personal preference and either can be good. Personally, I would go for the 7.0 but that's just me...