Yes, UC is Ultimate Compound. It is similar to M105 but slightly less aggressive and far more user friendly on a DA. I recommend you try that, especially if you have limited experience with the DA. Also M105 will probably be a bit much in terms of cut, as opposed to UC.
Use the yellow finishing pad. Burgundy pads are not recommended for use on a DA (except for when you put a MF bonnet over them and use them to remove wax).
Your paint doesn't look too bad and I think you could easily make it look great. Just remember to do a trst spot first and then inspect in direct sunlight!
