This increase may be added to the rent and security deposit.

Think of all the things that could go wrong and see if the lease addresses them: unauthorized pets or tenants, early termination, security deposit, lease violations, late rent, eviction, lawn maintenance, parking, etc.5.

Make sure to get a good lease and try to get 1 month deposit.

Long story short, the "master tenant" or so I was told, withheld the name and contact of the landlord when I moved in (listing found through craigslist), no contract was ever signed but got a receipt for the deposit amount I paid (approx half of first month's rent).

Do you have a checking account, a separate account for Capex etc, and a third account for holding security deposits, or do you holdall monies in one account and use accounting to keep track?

Question, once you found a private lender is ok just to have them deposit a large sum of money in you bank?

Do they give the deposit back to the tenant, then inform you there are needed repairs?

I require a months rent+ $50 as a deposit.

Hmmm not sure what foreclosure auction you're referring to, but technically it is NOT yours until you are deemed the highest bidder by the auctioneer (and put the deposit down at very  minimum). 

.- He partially paid ($1,600 of the $3,600) yesterday by visiting a branch and depositing directly into my checking account (which is his normal pattern).