Would hiring a  lawyer be cost efficient for something like this? 

I do feel my current vacant unit would be a good candidate for AirBNB as it is a small efficiency, but I don’t know how desirable the Hamilton area of Baltimore would be and the mechanics behind setting it all up.

We were able to itemize instead of taking the standard deductions on our individual tax returns while it was our primary residence, by deducting mortgage interest, taxes and qualified improvements, but then learned the power of the P&L and taking business deductions against the passive income to offset our tax liability.

We invested $4500 and believe those improvements added $6-7k in value and made the home more marketable.

I would focus on improving your credit first.

They do not provide meaningful oversight or guidance with respect to tax code compliance.A checkbook IRA LLC is an enhancement on the above structure that is generally more time and cost efficient for investors with a more diverse portfolio.

The refinance is going to leave us with about $20k left over, after the improvements.

I'm a fan of buying equity and then forcing more equity through improvements. 

We have some money in our Heloc to either buy another investment property or just buy ourselves a house that does not need massive work, good neighborhood and is energy efficient.

Yes, the mobile homes built today are more energy efficient than their predecessors, but they can't beat the solid interior and exterior of a Tiny Home built by a professional company.