According to REIA National, there is only one REIA they affiliate with in the DC area.

One caught my interest in Upper Marlboro MD which is a ways for me, and then their affiliate in Chantilly.

No affiliation but when I get a real estate license in Cincinnati this Fall, I plan on using this company:

I no have affiliation or will get any kick backs from any business they may receive.

or is Homesearch.com just acting as a middle man to sell this property for the major bank in lieu of the 5% buyers premium that I assume is pocketed by Homesearch.com and hence Nation Star Mortgage since Homesearch.com is affiliated to them? 

These guys used to rank up big sites for valuable keywords and make tens or hundreds of thousands of dollars per month off affiliate sales or Adsense revenue.

Are they a broker-dealer or affiliated with one?

Check it out at http://www.atlassian.comI have no affiliation with this company other than being a user of their products. 

I have no affiliation with any of the sites recommended (Except a customer on fiverr)

However if you decide to join they credit it towards the membership (Which I think is in the $120 range for the year).I also am not affiliated with any of these meetings, but I will say that NEREIA is my favorite REIA right now.