I get it from a basketball standpoint, but LeBron actually has a pretty big personality and has already shown enough in the acting department that I think he can hold his own across from Looney Tunes characters. I mean, not that his acting in "Trainwreck" was Oscar-worthy or anything, but he had no trouble sharing scenes with people like Amy Schumer and she's basically Elmer Fudd with long hair.
I do think a Steph cameo is an absolute necessity. Just so they can show him shooting the ball from another planet.