I am getting a very interesting education on these assets and the statute of limitations especially on lines of credit are very important to understand.Just curious if anyone plays in this space and can share some experience as well

For what you are talking about, an ADU, this is not a big enough contract for you to be fussing over the details and trying to play lawyer by writing your own.  

How would you guys play this if your max deal size was 500k?

Again, the probability isn't the issue as much as taking steps to play it safe.Can Airbnb check to ensure we meet these new covid requirements?

My mom just wants to make sure that she isn't getting played and needs to understand all the pros and cons. 

Being a developer and investor in Boston, the only way a property is going to be a "good deal" is if there's a value-add play. 

I think the best way to continue valuation is to add revenue and expenses from the house as if it were a rental and then add in all expenses, that way you get a full P&L picture and it negates the weird game the seller's trying to play with the expenses.

But another part of me realizes how nice it would be to have 35k extra dollars to play with.

@Jake ArnoldYou've really got a TON going for you and sounds like you can stack together multiple strategies which will ultimately really accelerate your growth.1) You are willing to move2) You are willing to rehab yourself3) You are willing to house hack with roommates4) You live in/near markets that cash flowYou are perfectly setup for owner occupied house hacks of multifamily properties with a possibility to transition to BRRRR or live in flips once you have enough capital.I firmly believe it's important to play to your strengths and what your market(s) allow.

If the seller won't play ball, I will then need to decide whether or not this is still a good investment.