I was wondering what your experience has been, good or bad with buying rental property in close proximity to the firehouse/station?

The biggest hurdle you'll have to overcome is accepting breakeven or negative cash flow at the start. 

Make sure you know the value the ADU will add to the property before building the ADU. 2) the financing on an ADU is typically far worse than for initial investment property acquisition or is often not leveraged by the ADU (HELOC, cash out refi, etc).

STR or MTR.  

I sold that in 92. next iteration was 2002 when I started a new lending company in Portland OR to specifically fund Turnkey buyers in the mid west doing BRRRR loans we killed that.

Is this the only market you are looking at to invest in or are you open to out of state investing as well?

Have you leveraged lines of credit, private lenders, portfolio loans, or other creative financing options? 

Partnering: If you're initially short on funds or experience, consider partnering with someone who has more experience or capital.

The property is a duplex on a street entirely full of duplexes and even a triplex or two. 

As the saying goes, “Whether you think you can or think you can’t, you’re right.”That being said, there are definitely creative ways to get into the game.