5 to 4 unit building

[Account Closed]

I have a 5 unit building that is 102 years old. We live in one of the units. I have it financed currently through the seller at 7%. I've been talking to a few different banks about refinancing and pulling some cash out for some much needed updates and most banks only offer 5.5%-7.25% rates, with shorter terms, meaning higher monthly payments for us; meaning less cashflow. 

So if I refinance it as a 4 unit, I can use a conventional loan at 3.5-4.25% at 30 years and increase my cash flow by a minimum of $500 from where it is now! Even with losing that small attic apartment!

My accountant says that I'm really not taking on any extra risk being that I'm the sole owner of the LLC as it stands.

I'm also wondering if I take that 5th unit and AirBnB it, is that considered an apartment? Or can I call it a "mother-in-law suit" where it could be somewhat connected to my current unit? Or is that asking for trouble?

Then with the cash-out refinance, I can update bathrooms and kitchens, and cashflow even better. 

Bottom line is I need to lower my monthly payment, and get money to do improvements. 

Any advise is appreciated.