As a landlord be symethetic to the tenants, and use your available resources to assist when they need it, but do not give into demands for situations outside of your control. 

Quote from @Tessa Tsui: You claim to have read those articles before, but you are using the wrong terminology and asking a question that is clearly answered by the resources Russell provided.

Is there a resource you can share?

It sounds like you are already doing move-ins perfectly with photo evidence and proper documentation.

We have quite a few resources here such as our STR Calculator, STR Newsletter, and our bookstore which has "Short-Term Rental, Long-Term Wealth" that is excellent. 

.), please describe for me the worst-case scenario for an eviction process if the tenant refuses to leave at the end of a lease term (assuming I do everything properly according to MA laws)?

It has to be handled in the proper way.

—and work with an accountant to make sure everything is properly documented.As long as your primary goal is to sell the property after renovating, your profits won’t be taxed like long-term rental income.

Proper structuring with professional guidance is key to achieving both parties' goals.This post does not create a CPA-Client relationship.

Give them proper notice and get them out2.