I’d first suggest One SL speakers as you won’t be able to use the voice circuity in the Ones so there is no reason to spend that money unless you want to plan ahead for using them elsewhere.

My room is pretty awful for surround placement too, what I did was place both in the corner, stacked one on top of the other but each facing along a different one of the walls. Nowhere close to the recommended setup but it sounds pretty decent for our room shape. Either a single stand behind the group or a shelf should work. Spouse may prefer the stand and no holes in the wall so ask first.

If you placed one in the corner and the second at the end of the group to the right of the two seats facing the TV the sound there should be pretty decent. Stands should work well for that.

What I did and a lot of others do is try every possibility. Place, then TruePlay and listen for a while. Pick the best sounding spot you and the spouse can live with. 

If you don’t have a compatible Apple device borrow one. You could buy something cheap on the used market too but once set up folks rarely need to run TruePlay again.

Follow up question. If I were to put them somewhere up on those window sills above the couch would that be too high up? Would it sound weird? Or should is that something TruePlay can correct? Just trying to think of an easier way than mounting on the wall.

I’d say they wouldn’t be too high to listen to, they would be too high for the best possible surround sound. Only your ears can tell you what works for you. Give just sitting them in the window a try before you start drilling holes. The ease of trying many positions is a valuable feature.

TruePlay couldn’t correct for the height issue but it will match them to your room and listening position.

Mine are at around seven feet to the bottom one and I’m not unhappy enough to look for another solution, like a lower stand in front of that bookcase.