It's cheap and just adds an extra level of protection.4.

Put the house under an LLC as I want to rent out the house (to provide protection)3.

This is business and in business do what's best for you and protect your investment to the fullest.

However, a 10-second search on Google pulled up the following: https://oregonrealtors.org/protect/selling-tenant-occupied-homes/

We have a 12 page management contract that we've added our real experiences to over the years, with the intent of protecting both us AND the landlord.

We have a vested interest in protecting our clients assets and don't spend money frivolously. 

because tenants are a powerful lobby group and they can and do change the laws to protect themselves....

I have an option contract to protect me from the owner selling after I start renovations.

I'm in Massachusetts, if that makes a difference, but I'm wondering what are the requirements for a new owner to be able to file a modification to gain the protection of the DPS status?

A heads up - before you send out your deposit accounting read the CA laws very carefully -  thankfully laws are changing to protect tenants from over charges from the security deposit - but this means there are very strict laws regarding this.