Technically, you must formally evict tenants.When you are doen, give your son a swift kick in the @$$ for letting this kid move in as well.

It was a swift and successful purchase with tenants in 5 days after putting it on the market and I also wanted to test my metal with regards to buying sight unseen (I only visited the house after having keys in hand).

I need someone with great and swift  comunication (i am abroad), responsible with personal aproach and patience (first buy).Please share your sugestions.

I knew the downsides of this type of investment but felt that our natural tendencies to over analyse everything needed to be combated by a swift decision and action. 

People are always in some sort of circumstances that have a financial factor and a wholesale buyer can bring a solution swiftly.

Be swift to fix their deficiency through proper legal action and either they get current and clean up their act, or they don't and they be come their Command/Installation's problem before it gets too far out of hand.

Imagine that all goes well and you prevail against the owner swiftly, with your attorneys fees and court costs approximating $1,500.

And most importantly, in your experience, does national tenants move that swiftly within the seller's 45 day due diligence period and offer their LOI to lease the property since they must do their due diligence as well?

You need to address this swiftly and professionally.  

But I would prepare to act swiftly once I became the new owner to address matters with this tenant head on.