Kevin: The only way I could see the bio-ball chamber working as a fuge would be if you removed that black grid. It wouldn't be very big, but all you would really need is a clump of chaeto, LR rubble could go anywhere else you can squeeze it.
Once everything is running, the sump will be fed by gravity. Before you start everything though, fill the sump to where you'd like it to run at, fill the tank until it starts to drain, turn on your return and everything should be balanced out.
Since you don't have anything live in your tank, just fill it with RO/DI water, get it running, and pour the salt in, that's probably the easiest way to do it.
-Justin