I've been reading a lot on BP lately about leases and I feel the one that my tenant signed 2 years ago is sufficient but weak. 

Something where the rental income could over or come close to covering the mortgage.These options would vary depending on the flexibility of the family needs (the more flexible the better) and also the amount of equity.I don't think the equity in my home would be sufficient to allow us a place to live and generate enough rental income to cover all expenses.  

@tony @Tony Marcelle, a letter of explanation in your credit file would be sufficient if you had an adequate credit score.

You will also need to pass the FHA self sufficiency test on 3- and 4-unit properties, which can be difficult in Boston.

The assessor is estimating the replacement cost of a typical home, not your exact home.The assessor may also consider the sales comparison approach, if there are sufficient sales of new homes that are similar to the one you are building.

A simple document signed by all (you, your wife, and in-laws) acknowledging this fact should be sufficient if the IRS audits you.

The silver lining is the quantity of section 8 tenants.

In addition to providing housing, they connect residents to other social services they might need and work to get them to a point of self-sufficiency. 

Generally, it's because the contract has sufficient contingencies the wholesaler cannot be forced to close if an assignee cannot be found and the assignment fee doesn't get paid until the assignee has received insurable title after the closing so the assignment fee is not at risk if title is found to be uninsurable.

Just in case you cannot finish the rehab, there must be sufficient money in the 203k to pay a contractor to do the rehab.