Put this in spoiler tags just in case.

I'd take them with a pinch of salt at this stage.

Bodies are usually credited as well

Are the bodies shown in Cokers credited?

I would imagine the cast list is there to put people off.

That said we could possibly see one of the sisters pulled from the water still alive.
I think one if not both are definitely dead, but maybe one hangs on a bit longer.

I imagine it would be Ronnie, so that Jack can say goodbye to her forever.
I think Roxy was already dead in the water when Ronnie jumped in.

No but Paul's body was credited.