If they gave possession of the property back you can claim the deposit for the last payment.

You need to take back possession of the property, rehab it and get it ready for the rental market or sell it. 

My question is since I'd be receiving July rent should/could I A) have her sign lease dated for that day but effective 7/1/15 B) wait until July 1 to receive rent and sign lease or C) don't take rent and wait until July 1 to sign lease and give possession? 

After the tenant has vacated and you have regained possession of your property, you will do your final accounting.

No free rent and if it comes down to paying them to leave, no cash in hand till they've fully vacated, signed a release of possession form and handed over the keys.

Two siblings living in the house out of 8 total siblings could have very easily led to years of lawsuits while your money is tied up in a house you don't have in your possession.  

If so should we commit to providing a certain time period they would take possession when we take deposit? 

"offers the grantee no warranty as to the status of the property title; the grantee is entitled only to whatever interest the grantor actually possesses at the time the transfer occurs.[2] This means that the grantor does not guarantee that he or she actually owns any interest in the property at the time of the transfer,[3] or if he or she does own an interest, that the title is free and clear" Any thoughts?  

Your contract gives you equitable interest in the property but you don't have physical possession yet.

Best way to "get around" such requirements is to comply, lease-option, delayed sale contract with right of possession or lease it and sell later.