I'd say that Jinbei will apologize to Nami for what Arlong did, and that's all. Oda has probably planned this arc for years, so I think that we're going to have plenty of new things, so there is no need for Arlong to return.
and why do you think he wants to Apologize to Nami? Obviously, Jimbei wants Arlong on sunny!!! because maybe he has a reason to hate humans and Jim wants him to be cured by adventuring with them or something… Jimbei is not the type of person who says "I am SH wannabe" he works alone!!!