The majority of the rehab was purely cosmetic, redoing the kitchen, bathroom, paint, and carpets.

It has always been interesting to me that the REI is not a pure supply-demand space because of the influence of the third parties.

It is purely a numbers game for them and they want to make sure they have a qualified buyer. 

So in that case you'd be better off going conventional with 85% LTV for a 2-unit and 80% for a 3-4.Lastly you could look at a DSCR (debt service coverage ratio) program, however those are intended for pure investment and carry higher rates, costs and longer closing times.Hope this all helps.

There aren't any "good" courses on how to steal owner's equity, not contributing to the value of real property and simply raising the price based on pure opinion.

This is pure luck and definitely not always the case.

That assumption is based purely off of Zillow's estimate so who really knows, but in any case,- Would it be wise to go ahead and obtain a HELOC on the property even if I don't plan on using it for awhile?

Speaking purely from the standpoint of you qualifying for another mortgage, you at least need to charge enough to reduce your debt burden and get your DTI ratio below say 50%. 

Then ask what it's worth for them.There's no time for them to accrue any meaningful amount in that time span if charging purely interest. 

For context, it's a $700-800k 2-unit MF, which I'm indifferent about in terms of going the owner-occupied vs pure investment route.