As a temporary set-up, do a group of yellow labs or rusties. One male to 3 or 4 females. Move them over to the 55 as soon as possible. Don't expect a molly to last long with them though.
You don't need dithers with mbuna or rift lake cichlids in general. I would personally prefer to keep more mbuna than take up space with dithers.
"In the multitude of counselors there is safety"
I think thats from Proverbs somewhere.
Anyway, thanks to the advice here, I won't try and use Mollies for dithers...sounds like they'd be "dinner" instead. I'll probably just return them to my LFS and and get the labs or rusties. I just love setting up a new tank...
Thanks again to all,
Jason