How long do I have to stop Lithium and Strattera before a liposuction & Fat Grafting surgery?

You need to ask your psychiatrists about when or if you should stop these medications. Surgery is stress and you don't want to have a manic or depressive episode during the recover phase.

There is no problem with you continuing to take lithium.   However, some anesthesia providers prefer for patients to be off of norepinephrine reuptake inhibitors, like Strattera.   Would discuss with your plastic surgeon and request anesthesia clearance.