Depending on the extent of the rehab, you can hold off on the rehab until the unit is vacant and not increase the rent as much (ie wait to pay $50K in rehab for 2 years and not increase the rent $200).

That means more or less you pay cash the day you buy. 

Some just have one meter and they pay the power and if you go that route the utility cost is very high.  

I’ll pay a monthly agreed upon amount to seller and have one year to pay off the full amount/find a loan.

In CA, that also means you're paying an additional $800 franchise tax fee per year.

I will be willing to pay a bit more to know that I can get another piece of filler stock without waiting weeks.But since I dont live in the houses I built and rent, I am looking for the most value.  

I wouldn't add it to the down payment unless it is necessary for cashflow, because the tenants will pay down the mortgage for you.

All four units are occupied and the tenants are currently paying their rent via cash in person.

Once I have significantly more, I think would go ahead and just pay cash for an investment property or fully fund a flip for an investor. 

So far I havent found any deals that would pay investors 6% and leave anything afterwards.