The attorney is not getting back to us I guess he knows he is not getting paid to do the extra diligence.

Hard or private money is usually short term. 

I don't think we will pursue this house since it is outside our price, but if we did I would certainly be making the extra space into a suite. 

The only way that I see it paying off is if you hold onto the property for YEARS, then maybe you will start to see your ROI but until then, it's just an extra burden that you would have to worry about. 

How long do rentals usually stay on market in Grand Rapids?

Usually at some kind of discounted price. 

I wouldn't take advantage of the situation, but I would consider throwing an extra 20% on top to cover unforeseen expenses.

Capital stack is usually a term used on large assets for the order of priority from debt, mezz, pref and common equity.Are they basically a hard money lender?

Prepayment penalties- usually 1-5 year terms.

HELOCS do exist for rental properties but you are usually capped at 65-70ltv and these will most likely require a full underwrite that takes into consideration taxes, income, dti and all the normal quasi-associated red tape.