Either BodyTite or Renuvion should help improve the loose skin that concerns you. BodyTite can be performed without general anesthesia which is a benefit. You can also combine either of these procedures with Morpheus8 treatments to optimize results. I've included a video I hope you find helpful.
I have done procedures like this, often combined with breast augmentation, but used Bodytite instead of Renuvion. I'm sure Renuvion can be helpful too, to get a mild lifting effect on the breast. Lying down won't impact the procedure in any way.
Yes, the first is using heat to help tighten your skin, and the second is a limited scar arm tuck for the upper portion of your upper arms. This is done to avoid the long scar of the full arm tuck.