Is it ok to have a tummy tuck if you have a hiatal hernia and peptic ulcer?

It will be tough for anybody to predict the effect the tummy tuck will have on your repaired hiatal hernia, but if you've had good control of reflux and acid and have a normal endoscopy, the tummy tuck procedure could be modified so these things won't get worse.

Yes, you should be able to have a TT with a peptic ulcer and hiatal hernia. The TT is unrelated. Tightening the rectus muscle can increase your reflux, however. Your peptic ulcer should be controlled as well. A consultation with a board certified PS would be in order as well as an approval to proceed by your internist.
Thank you for your quesstion, and good luck.