Hello,We have "trapped equity" in a long term rental condo and are considering selling it and doing a 1031.

How much will be the interest rate, and terms of the loan. 

@Carl RowlesI recommend a HELOC or Heloan on your primary residence or the rental if you have enough equity in either.

My father took out a $320K home equity line of credit (HELOC) to invest with my brother and I.

If your IRA receives an equity portion of profits from the business, it will likely have tax liability via UBIT that would be detrimental.Owning income producing real estate or interest from lending are passive activities not subject to UBIT. 

You can't pull money out if there is no equity.

When pulling the credit report one of the individuals has a high debt to equity ratio (50 %) My fear is what if this High DTI and credit usuage could result in one of the parties defaulting on future rent.

More doors the better if you are using an FHA type of loan.

Are you investing to create wealth/equity?

Due to the popularity and scarcity of these properties in Nashville, it would be difficult to find a property meeting the STR requirements given a proposed purchase price of ~$300-350k.Additionally, your situation is a bit unique as it sounds like you may be living away from your primary residence more often than not, and as such, I also recommend you confirm with a lender whether this situation would qualify for this type of (primary residence) loan.