Became very unresponsive very quickly, did not complete agreed upon work, made false claims about capacity and what they would do, etc.

This is straight from the CFPB website: "Additionally, for 60 days from the date your loan servicing transfers, your new servicer cannot charge you a late fee or treat the payment as late if you sent it to your previous servicer on time or within the applicable grace period."

Additionally, Airbnb income during this period could generate steady cash flow, though market conditions and regulatory risks should be considered.

I am offering 15% interest on the initial investment plus 40% ROI after a six-month grace period.

For quick math I have a range of each between: 700/yr to 3% of gross income

Sadly, on BiggerPockets, some are quick to label companies as scams without real experience.

Its a quick and easy addendum to prepare. 

If you're keeping the property and renting it for $2,900/mo, you'll make that $3,240 back pretty quickly.

Rented pretty quickly Lessons learned?

Lastly, we'll need a closing attorney who can close quickly and as inexpensively as possible.Any recommendations are much appreciated!