I usually recommend women stay off their side for at least a week. he pressure on the surgical area can cause some disruption of the tissues, as well as cause edema to pool on that side. The heartburn is probably a combination of your post-op medications, as well as the surgical...
I cannot see your flanks and back very well. You may be treated with a tummy tuck and liposuction to the flanks ("muffin tops"). But if the tone of your buttocks is an issue (and it may not be), consider a lower body lift (basically the same as a circumferential tummy tuck). ...
Can always be done as it does not further impair your blood supply. If your belly button is 'awful', consider having it removed and one reconstructed later.