My plan is to mainly focus on cash flowing properties that make the 2% rule. 

The property sat on the market for a month before an offer came in, but the buyer backed out at closing.

The buyers sittings on tons of cash waiting for market to change ( yield buyers ).

Congrats on those solid numbers!

Can i put a lien on the house for this. 

This all depends on the property.

., why aren’t they offering you a stake in the partnership?

Your buyer pool is essentially reduced to cash buyers, and a savvy cash buyer will figure out why they are the only offer on the table, and reduce what they are willing to offer in turn (since they know they can't refi to pull the liquidity back out of the house for redeployment elsewhere).

Be sure you to have offer for potential homesellers to raise their hand... like a Home Seller's Guide.Call expired and ask them how come they think their house didn't sell and listen to what they say. 

Another you could have done was to call a few other PM's in the area and get their take on the rent range.