Hello Suz- Some interesting thoughts here. I assume that this deal on this new home is a fantastic deal that you cannot find anywhere else in the area? That would be the only reason to truly get involved and close such a deal.
If it is such a great deal, I'd highly recommend you speak with a RE attorney soon to represent your interest. I know of a few that we do some business with. They would speak with you for a free consultation, but then of course there would be fees if they helped draft or review any agreements or deeds, etc.
You don't want to get burned. I like the guy from California's answer, but as he said - he is not an attorney, and also he does not specifically know Mass. state law.
If you need any further help, please contact me. Thanks and good luck,