Yes, if you have or obtain a HELOC you can use the funds for pretty much anything.

If I wanted to access cash it would then be dependent on the deal and I would likely lean towards pursuing a HELOC. 

I am not one to use a HELOC on my primary to invest .

This would typically involve taking a cash-out refinance or a home equity line of credit (HELOC) on your current rental to access the funds needed for the down payment on the new property.Regarding the lender fees, having two mortgages, one for the cash-out refinance and another for the new property, could result in additional fees, but it’s not necessarily double the cost.

Three part question regarding my HELOC. 

All six (6) lenders the owning spouse has contacted have stated that due to the way the property is titled in the SDIRA (75% SDIRA owned and 25% ownership in spouse personal name), the SDIRA would have to disburse the property totally from the SDIRA and deed the property into only the owning spouses name in order to provide a mortgage loan, HELOC, etc of any kind against the property in order to pay the spouse.

And if you need cash out, you should look into a HELOC, or a standalone second mortgage.

I'm thinking about using a HELOC to acquire the property and then refinance to pay back the balance.

I should have a huge HELOC to play with here once we're on the other end of our primary residence stuff.

Your expenses will include the HELOC loan and the mortgage, plus taxes, insurance, maintenance, etc.