You are definitely going to want to get a lawyer and as soon as possible.This will sound harsh.In your story, you have made a number of very poor decisions about how you purchased and managed this property. 

The rooms to rent are ready and overall the house is in good condition.

Now you have the Tenants Bill of Rights and every tenant now gets a free lawyer if you try to evict them.

I’m currently contacting a lawyer and will update what I learned here.

I would also discuss strategies with your lawyer for evicting/ejecting them if need be.

Right now you say it is $400/mo but in the summer it is much less so you need an average. you can't gouge tenants or you'll get a phone call one day from a lawyer. 

What makes you an expert that the unit is in a great location & condition and the market is hot, relative to the property manager?

With most auctions the buyer cannot get into the property and evaluate its condition.

The "typical" off market seller is someone who thinks their house is in too rough of condition to sell on-market, but doesn't have the money to fix it themselves.  

@Michelle Wang"My current lawyer has been somewhat helpful, though the case is progressing far too slowly.