Yeah, that’s a tough one. Especially with the window. It’s hard to say what to without saying what I would do if it were MY room.
A couple things anyway.
The rear wall is too for away for rear surrounds to be very effective. I would stick to 5.1(.4 later). Going from 5 to 7 channels isn’t a huge deal, and 5.1.4 is way better than 7.1 or 7.1.2, so I would just leave the rear surrounds out.(fwiw I went from 5.3 to 7.3 and then 7.3.4. 5.1-7.1 is subtle albeit worthwhile if you can place the speakers appropriately.)
I would also give in to my audio ocd and move the couch to the left to the last millimeter before it was in the way, and then scoot my LP until I was centered. Then, as you mentioned, place the right surround on the table, and the left on a stand. Both just behind the couch. Maybe a foot.
Also, being in the center, or that close to the center of a room is usually horrible for bass response as it tends to create holes in frequency response, and you might find bass lacking. You’d have to move the couch fore or aft where it is, but I don’t know how much it would take to make a difference. Maybe only a couple feet?
If all stuff just won’t work, then I guess you’ll have to do what you can. Surround sound does work best when you can follow the lines closely, but it’s not like your considerations are deal breakers. I would however still vote against the rear surrounds. Considering that particular space of course.