Ntare Guma Mbaho Mwine is a New Hampshire native and a dual citizen of the United States and Uganda. But he can easily make you believe he’s from either Chicago (“The Chi”) or Uganda (“Queen of Katwe”). Because he can play a refugee from the Angolan civil war in writer-director Ekwa Msangi’s “Farewell Amor,” you’d think the transformation from the son of academics and the grandson of an archbishop might be easy for him. While the onscreen results are effortless, they weren’t achieved easily. For one thing, Angolans and Ugandans have little in common, culturally or even linguistically.