Hi All,I'm planning on getting a HELOC against my primary residence to help finance the purchase and rehab of investment properties.  

Assuming you have a relationship with a local bank you could pool all that together in a HELOC.

My plan is to use the equity (either heloc or refi) to help fund another buy.

HELOCs are too hard to come by for investment property.

IMO, you have several options:  a) sell your existing as discussed above; b) keep it, rent it out and get a HELOC loan on it to invest into future properties if the rent covers the PITI mortgage plus the HELOC; c) purchase a multi-family investment using FHA, live there for a year letting the other tenant(s) pay its mortgage; d) purchase another multi after a year, move there ... ditto .... ditto .... ditto. 

@William Manzie welcome to BP.To answer your questions, a HELOC or 2nd mortgage might be the right way to go to get into your first multi-unit property.

If you get a 90% LTV HELOC before you move then you would have 120K to play with.  

Best bet on something that small is to secure it with something else, like a HELOC or credit card. 

And would the answer be different if the HELOCs did have balances on them?

So, if you can't qualify for a new mortgage And a nod a HELOC at the same time, you can't buy it, unless the seller does some owner finance type deal, which is probably not in her best interest.