I'm not a fan of in ceiling speakers for the fronts. They tend to have a couple problems. The first is most ceiling speakers do not angle enough to be aiming at you. If they aim mostly down they are not going to sound great. Most in ceiling only angle about 15 degrees. And the pivoting tweeter doesn't count, the whole sound field needs to aim towards the listeners. Most tweeter are too high of a frequency for dialogue and that is what we need most for TV. You need at least a 30 degree angle or better and only few companies make them, Paradigm, Triad, Episode, Deftech, JBL, and others.
The other issue with them is TV height. If your TV is mounted high on the wall such as over a fireplace ceiling speakers are not bad and can give the illusion the sound is coming from the TV. But if your TV is lower like on a stand or mounted lower on the wall the ceiling speakers are too high to give that illusion and that is why a sound bar might be a better solution. If you have the ability for in-wall, on-wall mounted or freestanding that would be better but since you are looking at in ceiling speakers I figured those weren't options for your situation.
In wall or in ceiling is not a great choice if you want to rearrange the room. The speaker bar would be the best choice for that. Mount it under (or above) the TV on an articulating arm mount and the sound will aim whichever way you move the TV.
I see your wiring and can give a couple suggestions if you want to use that wiring without extending down the wall. An on ceiling speaker could work. The Thiel Powerpoint are a good speaker but not inexpensive and you'll have to decide if they match your decor. But they would work for your situation.
Make a valance or soffit and mount speakers behind it using a speaker cloth. Match the color of the soffit to the speaker cloth. Aim the speakers at the listeners. Or you can make an angled soffit or valance and put in wall or non-angled in ceiling speakers in it.
The round in ceiling speakers give a small amount of flexibility in being able to rotate them to aim at the listening position. You won't be able to re-arrange the room but might help if something slightly off center. Of the brands I mentioned you would have to look at Paradigm, JBL and JBL's big brother Revel (which I didn't mention). All make round models with decent angles. The Paradigm CS-60R-30 has the least amount of mounting depth <5". You would have to see if it will fit.