Xiamen University to T3 and good food near XMU/Nan Putuo

Do you refer to Siming Campus of this university?
If yes, take bus no.52 to Dianhua Sushe Bus Stop. Then walk north around 30 meters to get to Wenping Road Bus Stop. After arriving, take the airport shuttle bus to Airport T3.

About the seafood and dimsum place, the following two are recommended:
Xiaoyu Seafood Restaurant: No.296, Zhenzhuwan Huayuan Community, Huandao Road, Siming District
Wuzaitian Local Food Restaurant: No.25, Meihu Road, West Hexiang Road, Siming District