I probably wouldn't keep the home with negative $550/month cashflow unless you have serious reserves and sufficient bulletproof (as in recession-proof) discretionary income.

With FHA loans, there is a self sufficiency test.

Most houses cannot be bought at a price sufficient to cash flow.

We've touched on this prior to the 'settlement' that today lenders essentially allow the real estate commissions to be rolled into the buyer's transaction by appraising for a price sufficient to cover the RE fees.

Most seller financed deals are to borrowers who lack sufficient credit to get a conventional loan, so their risk of default is much higher.

Your primary insurance policy with $300,000 in liability coverage should be sufficient in 99.999% of all lawsuits.5.

I don’t believe 10k is sufficient enough to really do a deal on one’s own for the most part.

Given that the borrower had given us sufficient time to complete the loan processing and clear all title conditions, we were able to arrange the financing with one of our multi-family lenders at a rate that was actually lower than the prevailing rate when the borrower initially contacted us.

You don't need anything significant drawn up for the loan agreement either, a verbal agreement may be fine or just an email exchange can be sufficient (you could sign if you realllllly wanted to). 

If the person who emailed you has the authority to release the agreement, then I'd say the email is sufficient