It all depends on your investor profile.

Loans like this can be useful or very dangerous, depending on how you manage your business.The ideal situation for a loan like this is when you have a property that will take a while to get up and running. 

Looking at, and that depends on getting an 80% LTV on heloc/refi, at 600-650K 

If it is someone you know you can give them a straight return as if its a loan - can provide a lower interest rate to provide upside - it really depends on the lender and what are they concerned with and what is their risk profile. 

The biggest thing with 5+ units is everything is more expensive, and the inspection requirements (depending on the municipality) are often more rigorous.

If you have one of the older, turn of the century mid town houses, you are probably getting somewhere around 1600-2000 depending on the condition of the home, availability of a garage, etc.It is an older home, from the 40s I believe.

However, Minoan doesn't have an efficient business model. 

If your willing to do so, you can live in the casita and then rent out the main home and have your tenant pay the majority/all of the mortgage (depending on what type of deal you find obviously). 

I own the property free and clear and i use the equity as part of my business line of credit.

There are always opportunities in buying real estate, businesses, companies, etc., as long as you know (or think you know) what you are in for.