Do you want form a partnership, an S corporation, or a C corporation?

This can be problematic as it can put the buyers brokerage into (implied agency) with the seller as they have to tow the line between ministerial acts and those that can be considered to form a client relationship.

One super important thing that I rarely see discussed when this question comes up is this: If you do form a LLC and take the property in that entity (whether directly or by quitclaim deed shenanigans), make sure you legitimately treat your LLC's operations as separate from your own personal financial operations.

For the future, you don't have to send it certified mail, there is a Certificate of Mailing that's less than $2 that certifies you mailed something on the date you said you did and to what name and address it was mailed - you do usually have to wait in line and ask the clerk for the form as they don't put them out like Priority or certified forms, but I do it for security deposit returns and other important documents. 

Congrats, I personally would factor your vacancy/repairs into any sort of "pro-forma" return.

I always tell them to email me the "pro forma" numbers; acquisition cost, rehab cost, ARV and expected hold time.

Putting aside "pro-forma" cash flow for a moment, are you paying a fair price in the market's opinion? 

Do you form a JV with them?

This is the basic info, but that lack the vision....The vision starts with fact that it is located right across the street form a very prestigious college.

Don't get hung up.State specific, but even in California, you don't have to form a company, website, and advertise to be in compliance with the law and not have to buy loans from a broker.