My wife and I are moving into one of our apartments (4 plex) and I'm wondering if, because we will be living there as a primary residence, are we exempt from any of the renting laws?

He wants to keep his residence in the family and intends to put it into a revocable trust. 

Personal residence.

I'm a little bit confused about the process of going through the MassSave program in a multifamily rental property in which none of the utilities are actually in my name - I was told that setting it up with the electric account number for one of the tenants is the simplest solution, but I'd prefer not to have to go through them to get it all done.

It’s not cheap but it’s a good solution.  

I have $50,000 to invest in real estate.Question is: What if I rented out my personal residence for at least the next 3 years?

You'll have some locals provide some good solutions there. 

Yes you're supposed to live at the property for at least one year as your primary residence which means at least 51% of the time. 

I don’t think this would get the tax breaks you get for a primary residence

In fact I have all of my properties in trusts which makes my residents a part owner in the property and they are required to take care of all the upkeep and repairs on the property.