@Sean Tift I'm a private lender with expertise in BRRRR.
You may want to go DSCR / private. Here you can get up to 75% of the Appraisal Value back to pay off the HELOC and turn some equity into cash.
Qualifications are credit score and DSCR (which is essentially a measurement of cash flows). So, to answer your questions, you'll want to make sure the property is occupied #1. Then consider the monthly taxes, insurance, and an estimated P&I payment. When taken against the rental income, if you're in the green, you ought to be good to go.
DSCR lenders also offer 30 Yr Fixed Rate loans. No balloon or term renewal. Fully Fixed Fully Amortized. Generally embedded with some variation of a PPP, so consider your time horizon and exit strategy.
Not much else besides the primary benefit of private / DSCR is that it's "LITE" doc. So, no tax returns or income / employment verification. Like I mentioned, credit + DSCR. Liquidity shown via bank statements. The mortgage generally doesn't show on credit reports either. Though you'll personally guarantee the loan, the transacting party can be your entity.
Hope that helps.