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. 

HELOCs on rentals are rare, and depends on where you are located.

We then will either sell or keep it as a STR depending on what makes more sense for us. 

There is a lot of variability in this answer and, like all things in real estate, it simply depends. 

Depending on the loan product, you may be able to exclude business debt once the business has paid the debt directly for 12 months.The income and losses related to the operation of the entity will affect the income side of your DTI (like Jay explained) if you own 25% or more of the entity.

HI @James TobinAs you get into the RE market, regardless of where you choose use this website as a good starting point to find out what the areas are likehttps://www.areavibes.com/Best of luck from Fort Worth 

Colorado is pretty dependent on tourism. 

 WE  do both  give me a call and I can explain but depends on where the tax advantage is

Investment property (not primary residence)So it depends on the type of financing.

If a HELOC isn’t an option, alternatives like a home equity loan, business line of credit, or a DSCR loan could work depending on your situation.