Over time, I’ve accumulated more cash reserves and don’t need as much flexibility, but I’m actually in the middle of a refinance right now using an interest-only mortgage—because the pricing with the lender and the corresponding ARM is more favorable than a comparable principal-and-interest loan.The key with these alternative or "exotic" mortgage types is that you need to be financially savvy and have a solid plan.

12 or 24 Month Bank Statement is probably the best bet.

Currently I am reading "Buy, Rehab, Rent, Refinance, Repeat" by David Greene and tuning in to a lot of Brandon Turner video and content.

refinance our own home with some money down + purchase another flip? 

Then refinance it.I just don't have that amount of "cash" but i have enough as collateral. 

Sara,I see this a lot and I always ask if you know you are going to refinance in the long run to consolidate the Heloc why not just do a Cash out refinance instead. 

Sounds like a cash out refinance would be the best way to tap into that equity. 

To adapt, focus on refining your ARV and repair cost estimates, explore off-market deals, and consider creative financing strategies like seller financing or partnerships.

I used a heloc to purchase the first 4 rentals, so $155k of dept is wrapped up In  that until I refinance each property which have already appreciated extremely quickly given the current market. 

The other way to satisfy is to get the property owner to refinance but that is not always in your control.