So I have your wish list as CO beach during the day, stay on Fench side, Dutch side night life and near a casino and easy-ish driving at night.

Club Fan is a good choice for some of your options as would a rental in Orient

Cupecoy offers a CO beach, albeit no guarantee of a beach at all some days, near casino and night life. To stay on the Fr side and keep Cupecoy in the loop you would need to rent in Terre Basse, there are 1 bdrm rental thru sites such as VRBO

Or consider staying in Cupecoy area, lots of rentals, gives you a CO option if there is beach, casino, night life and you can drive to Orient during the daytime for a better CO option and if you want some dinners in Grand Case, then consider a cab.

Or if you want a dependable CO beach option then stay in Orient area and consider a taxi for your night excursions?

Going to be hard to get all on the wish list exactly, but still doable
J&B