You can always leverage rentals within their ability to service the debt. 

Unfortunately, there are times when being accommodating and making exceptions can lead tenants to take advantage of the situation.

It will likely be a web of contractors, engineers, and architects, but some those are ultimately leading to the developer. 

One factor to consider is your interest rate on the debt.

There might be some hoops to get through with conventional financing with your income situation, but if that doesn't work, you could use a debt service loan.

I've only ever sent out an offer like that once, and that was to a preforeclosure lead that refused to discuss the property, instead telling me "that's not how real estate works, just make me an offer".  

OR refi one at 70% and get the 45k loan leaving some debt on the line of credit but keeping home 3 free and clear and adding a lot of value to it as well as getting some really good rental income from it.

Also, do you have enough equity that if you sold one you could pay down most of the debt on the other 3?

If it were me, I would buy cash flowing, seller finance deals, keeping my debt to income low, low down payments and negotiate competitive terms.

Here's the breakdown of rental income and expense analysis:1.Annual Gross Income: $25,800 (Monthly rent of $2,150 x 12)2.Annual Expenses: $25,800 * 0.40 = $10,3203.Annual NOI: $25,800 - $10,320 = $15,4804.Annual Debt Service: $10,680 (Calculated previously using a mortgage calculator with a loan of $131,775, 7.25% interest, and a 30-year term)5.DSCR: $15,480 / $10,680 = 1.45 (approximately)