Many will come on here and tell you of other options and those are good ideas however in some low income areas cash is still king and the easiest way to assure you’ll get your rent and in time .

If you delead, and maintain the standard, you will be in the clear.Here's the law (emphasis added by me):460.100: Duty of Owner(s) of Residential Premises (B) Whenever any residential premises containing dangerous levels of lead in paint, plaster or other accessible structural material undergoes a change of ownership and as a result a child younger than six years old will become or will continue to be a resident therein, the new owner shall have 90 days after becoming the owner to obtain a Letter of Full Compliance or a Letter of Interim Control, except that if a child younger than six years old who is lead poisoned resides therein, the owner shall not be eligible for interim control, unless the Director grants a waiver pursuant to 105 CMR 460.100(A)(3).

I had a broker a few years back that was really good with the legal part of the business, making sure that we were in compliance.

If I keep taking the checks then an argument can be made that I've accepted non-compliance with the lease terms. 

I can assure you it will be very difficult , most will give up you will literally need to become a new person you will get your nards kicked into your throat the first few years and probably not make a dime for a while but eventually you’ll look back and see it was worth it .

As an agent and investor that flips houses - I offer a buyer's agent 3% every time and I believe it nets me more in the end.Remember too - the buyer has about 20+ exits from a contract if their agent knows what they are doing (option, EM, termination due to seller non compliance with delivery of items like survey/T-47, third party approval, appraisal etc).  

If you don't have local counsel, I'd have my lease reviewed (or modified for the future) so you are in compliance with state and local laws.

I was assured then that I was priced too low but moved forward to honor my commitment etc.

Code compliance. 

Also- I think there are some pretty strict restrictions on STRs up north so make sure you are in compliance with those.