OP,
In a similar situation as you are, building a dedicated listening room....unfortunately mine will be on a tight budget. Some suggestions, many of which you've already considered.
(1) Power is crucial, you are already know this.....I would recommend using high quality receptacles like Furutech GTX-D(G - Gold), Furutech DTX-D(R - Rhodium), or Oyaide R1.
(2) If you are going to stream, make sure you have a high quality ethernet or mesh system that you can connect a streamer into via an ethernet cable
(3) Reach out to GIK Acoustics (Mike Majors is a really helpful designer), their assistance and software has been really helpful. The one thing he highly recommended is to not overly deaden the room, it's hard to overcome this failing.
(4) I'm using hardwood floors with area rugs to "tune" the room, has been recommended to use thick tight weave wool rugs
(5) When placing receptacles, think about how your cables will lay in relation to signal cables, speaker cables, and power cords; so you can keep crossovers to a minimum.
Good luck on the build, sounds like you're starting from a great place!