As for using the other system for music. It’s difficult to get a real feel for the space from a sideways picture, but if it were mine, I’d try a couple things. First, I might try and get those mains a little closer to the display. From the pic angle, it looks like you could benefit for 2ch as you mentioned soundstage/imaging problems from being too far apart. Also, it could help with off screen panning with movies. Ime speakers too far off screen will make pans teleport from the side of the screen to well past where you’d expect them to go. If there’s room, “I” would put the sub in the corner, remove the acoustic panels and scoot the mains in. See what it sounds like. Heck, maybe try the NHT’s as mains too, cause why not?
Also(going off memory still) it looks like the center could come either all the way forward to the edge of the stand, or up in front of the tv. Although the tv might need a riser for that. That should help acoustically, and put the tweeters on the same(or closer) plane.
Ok, back to honey-do...
