So both parties or all tenants that should have a score of 600 and above.  

The law requires you to give a written (not oral or email) 24 hour notice of any entry.

Some or all of these trips can be written off on taxes as well, so consult your accountant.As mentioned, Trulia's maps are a great place to start.

I've recently closed on a few deals and about to close on a few other using cash and after I refinance I hope to get almost or all of my money back out.

You will generally give up most or all of the Option fee (Which you would still have to credit the buyer as part of the down payment if they do exercise), but it is the same as a rehabber paying for the wholesaler to find them a property that is locked up.

Or all three?

Then explain to the remaining tenants the full amount is still due , whether 1 person it there or all 5 .

They may pay up for three month, then they will try to cancel some or all of the stay, requesting a refund.

There is a pecking order for buyers accepting which offer when multiple bids come in (assume all bids have same offer), and it depends on the down payment or all cash. 

My best advice would be to divorce yourself from the notion that you will clear money like all those emails bigger pockets sends out on a daily basis of people buying place with no money down, or making 2000 a month from homes less than 100k or all the silly things they put out on a daily basis.