I go with half-half. If I'm writing from Charlie's point of view, then I would refer to him in text as Charlie (because I don't see him thinking of himself as "Crews") but he would think of Dani as "Reese" because that's how he sees her. (And, naturally, vice versa if the fic is from Dani's pov.)

Charlie's pov:
Charlie was eating a banana. Reese turned to him and groaned, "Crews, can you not?"

Dani's pov:
Crews was eating a banana. Dani turned to him and groaned, "Crews, can you not?"