If the market continues to appreciate, holding the property could yield more long-term equity gains.

I'm not sure if the program is still going on, but has definitely revitalized a lot of the area when it was once destined to follow the way of other older cities that are aging out of existence both in terms of people and property. 

I am considering getting into this space (looking at some courses), but worried that its too late, and that deep local market knowledge/understanding of buyers/connection with developers etc is required to make this work, which only incumbent/long term investors will have and would be hard for a new entrant starting from scratch to catch-up...is my hypothesis valid in your opinion ?

The sooner you regain control, prove that you fully intend to enforce the terms of your lease, and that you will not be 'played' by their recall of events or documents, the more effective this action will be.  

Long term intelligence of this move is to be seen. 

although I'm skeptical of going with her service, it is pretty logical because she would be helping me rent out a property long-term but sublease it for Airbnb.

Flipping, renting, or sitting tight for long-term appreciation-there is potential for anyone willing to do the work.

It’s been a long journey to get to this point, and we even had a failed attempt with another PMS (but I’ll keep those details to myself).

That's why mature investors with long positions like Boston while places like Brockton and Holyoke are more affordable.

For example: We provide tax preparation and advisory services to people who invest in commercial (including multifamily) real estate, and high w2 earners investing in short-term rentals.