Home will require a full HVAC upgrade this fall, but several other big items have already been replaced or were upgraded/replaced by the previous owner.

Even posting it here in full detail would be good for other community members to see.

I'm in the process of doing a FULL rehab on two houses that are on one parcel.  

Instead of 'returning' deposit from '15, and having two remaining write new check, can anyone suggest wording/letter that I could have the moving out tenant sign stating something along the lines of 'I, ____, have received my full deposit back, including interest, from my roommates Xname and Zname and do not expect any additional monetary return from my landlord, _____' ? 

The balls in my court now, and the only thing holding me back is I am afraid I can't manage another 48 units, full time job and most importantly, be a great dad and husband. 

They are prone to human error.

I'm thinking of a scenario where I have an investor who wants me to operationally run the flip, but they don't have enough cash to be the full lender.

If I could also possibly become an asset to a Note Business Company, I can offer my full commitment to the business. 

If tenant wasn't on subsidized housing, do you think tenant would be paying their full rent amount on time, every month?  

You should certainly never pay the full price ahead of time, and for large projects, draws are often the best option.