We also brought rents up to market on all the units since we purchased the building.

He brought on the 2 roommates (who were background but not credit checked) and all 3 signed the lease. 

What state are you buying in and what brought you to that market if I may ask?

Long story short, I befriended a 75 yr old woman at a dog show and she brought me this offer.

Your agent might be able to sue you for fess they acquired in good faith effort to sell your property - marketing, includes pictures etc. this can go into other things based on a procuring cause as well when breach of contract has been established;If you went the FSBO route after ‘firing’ your agent, any buyer that came through that was a result of the first efforts made by your agent could be grounds for a suit of commission as they were the original procuring cause (they technically brought the buyer to your property first with their efforts), if you went on to ‘bad mouth’ your agent a subsequent defamation suit could possibly arise.

I brought this investor into contact with my son-in-law.

They brought you the deal, and will be acting as the PM on it. 

Another agent brought it to us and we offered a solid brice with a leaseback addendum the sellers needed.

This property was illegally used as two 1 bedroom apartments but must be brought back to it's original use which is 4 studios or efficiencies (as some like to call them). 

I found someone to partner with me that brought the lending ability.