REITs are required to pay out a minimum of 90% of their taxable income in the form of shareholder dividends, so no REIT is going to fit the bill.

Possible that one present owner may stay in as a minor shareholder.  

The company C-Corp needs cash because 2nd generation shareholders want to retire.

My business partner and I are 50% shareholders and plan to acquire additional properties which we will divvy up when we dissolve the business in 5ish years.  

Due to unforeseen internal issues with shareholders, the focus and funding towards scaling was halted.

Those generally eligible to claim this tax credit are corporations, trusts and estates, individuals, and shareholders, partners and beneficiaries of a passthrough entity.What are the requirements to qualify for this credit?

Shareholders contribution. 

Also, if he is providing capital I have been told to write a shareholder's note. 

If the HELOC from property A was used for personal use, the interest (beyond returning share holder equity) wouldn't be deductible because it is not a business expense. 

Unless the mortgage is owned by a private party it means that interest belongs to the bank’s shareholders and management has a duty to protect that Loan and uncollected interest.With only the possible exception of Texas (?)