2) When you present an offer you tell the seller you don't know who the buyer will be when he signs?

We could have withheld and deferred three months of rent, which would have been financially devastating to the owner.

From my experience watchibng several BP webinars that cover analysis of properties , the presenter usually highlights an estimate of 5% of monthly income from a propety for saving for capital expenditures.

How can I ensure that I'll get paid before I present my buyer with the deal?

Have them write the offers on your behalf and let them present those offers to the owner.

It is happening next month with a presentation on owning vacation rentals.

They watched a presentation about the area's potential.

Now lesson learned: always check public records to ensure all needed signatures are present on the contract and subsequent closing.

This is assuming that the numbers  are as they were presented. 

cash flow is OK .. 100% occupied but tons of deferred maintenance and renovations needed. in and out.