I have had one realtor bring me buyers for five different houses in the past.

In most states, including TX, the owner must disclose the inspection to future buyers, by law, so he/she loses and the future buyer gets the benefit of my hard earned money. 

He might be right, and since we are first time buyers, it makes sense.

I have found a buyer that is offering 36k.

You were essentially not in business unless you were a true cash buyer though.  

There are several approaches to doing lease options, and consequently, many variables... so it would be prudent to do so to 'maximize' the exposure, pre- screen the largest number of applicants, increase the likelihood of 'closure' (selling the property) with the tenant buyer(s) and structuring the deal, to optimize your ROI.

Regarding numbers, since end buyer will pay off the mortgage that owner owes $40K plus what he’s asking $48k, where ARV is about $53 only. 

Most areas are slowing down because of lack of inventory, not lack of buyers; if this is the case in your market, you may be able to get buyers before your flips are completed, by using "coming soon.

I guess I wanted to get an understanding of how a conversation goes between an agent and buyer.

. :)I used to list, negotiate and represent buyers of short sales back in the hey day of the market crash.