For example, each of my properties has a main account and the sub-accounts under that for CapEx and security deposits.

There’s definitely a lot of opportunity there, and I'm sure you'll find it both rewarding and challenging.A key part of successful fix and flip projects is securing the right funding.

Security deposits require separate handling - they should be placed in an interest-bearing account.3.

Some arbitrage operators also try to get multi-year lease terms, security deposits waived, free rent up front, and the like.

It has worked so far, but there are few things about it that we've had issues with (security deposits, rent receipts, etc.).

You should use a state-specific lease that is clear regarding the start and end dates, the monthly rent, the fees that will be charged (ex. pets) and those that may be charged (ex late fee), the amount of the security deposit, and a clear list of rules associated with the property (no smoking inside is a big one as are rules related to parking).

@Dan Dares TMIf the "investing partners" are going to be passive, you need an SEC attorney since you are now creating a security.

Nope, too much of a security issue! 

This is because Mortgage backed securities are in direct competition with investors looking for "safer" investments backed by the full faith of the United States Government. 

After  exhausting security deposit is sometimes less expensive  to give them a stipend to leave.