He get's principal and simple interest payments over a number of years.I'll manage the deal and the property.Looking to create a proforma for this that would fit a typical rental analysis but insert the detail of having private money cover the DP.

Typically a new roof only makes sense to protect the asset.

The easiest solution is typically keeping water away from the wall. 

Regarding costs there are a lot of factors considered but to give you a ballpark idea, here is a brief scenario: Our main office is based out of Cherry Hill NJ, a typical 3 bedroom row-home lead-paint inspection in that area would cost on average $450, however we can service the entire state of New Jersey (North Jersey office in Montclair, NJ). 

Typically, I avoid using a series LLC in Illinois because each cell requires state registration.

Reason being HML's are typically short term loans that are interest only.

Typically to grow a real estate business and raise money you are better off partnering with someone.

As for how much I’d put down, it typically ranges from $0 to $100K, depending on what I’m bringing to the table or what my partners are contributing.

Owning a STR is not like owning a typical house, even a LTR.

Remember that if you buy 5+, typically that is going to be commercial lending and that can be tougher to sell on the exit.