Post FUE, would it be ok to have nicotine and tobacco-free hookah (shisha) 2 weeks after the procedure for social smoking?

It is best to contact your doctor about post operative care and instructions since each doctor has a different regimen.  Most doctors would say smoking is bad for new grafts but there is no studies that prove or disprove this idea.

Smoking is bad for hair growth & your health in general. Smoking substitutes carbon monoxide fumes for oxygen in your cells. Smoke as little as possible.

Smoking and use of nicotine are unhealthy in general and are best avoided.  Nicotine in any form makes blood vessels contract and can impede circulation and healing.  That said, most likely after two weeks the nicotine will not cause any major problems with your transplanted grafts.