It sounds like you're existing portfolio may not qualify but there are several companies offering 30-year fixed on 1-4 unit residential.4) Build up  a cash cushion to see you through any high-interest period.

This gives me a maintenance/CapEx cushion from the outset, if there’s a break down or emergency.Second, the property seems poorly managed.

I would double, maybe triple that for the first couple years at least to build a nice reserve cushion.

That could give you a bigger monthly cushion and push this into a favorable and valuable deal for you.

Please show me your bank statements to provide some amount of assurance that they have some number of months cushion so they would continue to be solvent in the case they get sick or in some way can't drive / perform the activity. 

I have been reading everything I can get my hands on for the last year and have a decent cushion to pursue my next property with the goal of 15-20 cash flow properties. 

Bottom line: You’ll need cushion (read: money) for some degree of rehab and a higher opex.

So, it is tempting to sell and get the cash as a cushion...but I also planned on having that to pay off the main residence one day.

AND with an additional caveat: the PROVABLE cash flow from the property must service the debt with a cushion of at least 20 -25%, so a debt service coverage ratio of 1.2 - 1.25.That being said, the 'gap' can, in some cases, be filled by seller carrying back a second lien. 

My question is if my mortgage on the property is say 350 and it's renting for 550 won't I technically be negatively cash-flowing due to the probability that the 40% cushion initially factored into the deal will probably cause me to have to put a small amount of money in monthly?