Dangerous to Have Breast Lift, Tummy Tuck, and Arm Lift at Once?

Hi there,
Not enough information to give you a credible answer. Maybe yes if the surgery time is relatively short and you are in good health as determined by your primary care doctor. Maybe no if you are not in good health.
Good job about your weight loss. That will go a long way in helping you actually "be" in good health.

Combining all the procedures that you mentioned may be a bit too much for you.  This is something that is based upon your health and also the amount of time the procedures would take.