Added cheap square footage and improved features - ie. additional bedrooms, quality outside space, and upgrades throughout

STR regulations are a big consideration before you make any big capital improvements specifically for short term stays, also running your numbers and making sure that your area offers consistent returns above what you'd get renting it long-term.

Either the rates improve and it can cash flow with a long term mortgage or I can sell it when the market improves (I feel like both will happen at the same time). 

I'm hopeful that this project will bring additional businesses, housing, and improvements to the neighborhood in booming town. 

Exploring different loan programs and possibly adjusting the down payment to improve terms.

HI Sherrie, ADU's are generally a great return on investment..I'd double check the DSCR and FHA rates though...A DSCR cash out client was just quoted the high 7%'s to very low 8%'s and FHA have improved tremendously this past week...on purchase quote today FHA rates were in the high 5%'s..check in with @Joseph Chiofalo Good luck! 

If your building is the problem building then you need to clean up and I would probably give everyone 60 days notice to get out, rehab and improve my tenant quality.

Are there ways to improve profitability or add value to the property beyond its current use?

Improve Efficiency – By classifying and identifying the various components of your property, a cost segregation study can help you maintain and manage the property more effectively in the long run.

I’d still like to leverage my skills and experience with home improvements.