Both properties have a substantial amount of equity that’s essentially sitting idle.Would it be a good idea to tap into this equity (through a HELOC, cash-out refinance, etc.) to fund future fix-and-flip projects or purchase additional rental properties?

funds only go into interpleader after months of sitting in escrow. the court just does not hand the money to the seller either.. if not agreed upon the funds go to the state etc.

Ideally you would put only one persons name on the mortgage unless you absolutely had to have both to qualify.  

I got approved for a HELOAN on my primary property but not sure if I should take the loan to just use as “leverage/reserves” to show the HML and get funded.

Non-recourse has less personal exposure, but you need a very strong balance sheet to secure this without bringing in a KP.

Funds are beginning to run extremely tight.   

I'm really busy with my w2 job working all the time to fund my investments. 

Quote from @Roger D Jones: Quote from @Fred Scott: @Roger D Jones:  Any insights on why the North Carolina purchase in Fund IV makes you nervous?

Alternatively, your sibling might use a 1031 exchange to defer taxes by reinvesting in like-kind properties, though this doesn't directly fund a primary residence.Other ideas include leveraging a HELOC on the rental properties for the down payment, taking out a 401(k) loan, structuring an owner-financed agreement, or a lease-to-own arrangement.

Well, three top reasons come to mind:It will allow you to deduct their earnings on your own tax return.It is required by law for any person to whom you paid at least $600 in 2023, total.