I am in a very similar circumstance as you. My space is about 11x16 which is similar to your usable space. The pool table area doesn't count other than the sound waves bouncing in odd areas but that's OK.
My first recommendation is upgrading your HDTV. You can get a 55" 1080p OLED set, delivered, for under $1,700 or, if you want to spend some real cash, LG is coming out with the B6 4K OLED with the best picture EVER in a couple of months. Guess is the 65" will be between $3,500 and $5,000 MRSP.
The reason I mention the TV first is I think you set your couch too far from the TV. If you can move it so you're a couple of feet closer, especially if you go with a 4K, the last set up of the 5.2.2 by Latent would be perfect and you could move the surround speaker closest to the couch forward a bit so it would align with the one next to the sliding doors.
I understand you can move your TV closer which would be fantastic with the OLED 4K set but moving the couch closer permanently allows better placement of the speakers.
You could still do a 5.1 that would sound great and the savings on speakers and receiver could put a few hundred, or even over a grand, towards the new TV. Even a 7.1, with ceiling speakers only used as rear speakers, would be nice without the expensive receiver.
However, if you have your heart set on a 7.2.2 setup, I see no reason why you couldn't have ceiling speakers as the rear speakers as long as they're fairly far behind, particularly if the surround speakers are set at ear level. Although it would look like a 5.2.4 it would actually be a 7.2.2 setup.
As far as the surround wiring issue between the slider and window it really depends how much labor, and/or money, you want to spend on hiding the wires. Outside of the main speakers the surrounds are probably the most important. Personally, I think latent's 7.2.2 diagram is good if you eliminate the rear speakers and use the rear ceiling speakers as the rear surround speakers if you go with Atmos.