How would you set up a home theater in this room?

I would go with two One SLs on speaker stands (see photo). You should be able to easily hide the power cables under the couch.

An issue with speakers behind the couch is proximity to the listeners. For a listener at either end of the couch, the nearby speaker will dominate. The center seated listener will experience balanced surround. If a single listener is typically lounging on the couch, the surrounds could be balanced to favor the listener’s typical orientation.

I recommend preparing for potential future developments by installing wire for four ceiling speakers, but only document their location at this time, don’t install anything.

I’m also anal about network wiring. Install lots of network ports scattered throughout the house and run some fiber for critical locations, such as TV sets and an office cluster of equipment. The fiber will be “dark” for a few years, but eventually it will be welcome. Ceiling WiFi access points are more potent, if you go this route, wire now. Another reasonable approach is non ceiling, wired access points in most rooms. Regardless of overall potency, a nearby access point will be more effective than a distant more potent access point.