After completing wang dang atomic tango, I noticed that Old ben can't be hired and Fisto can only be hired once. You can pay the robot to go to your room, but the continuation command disappears after the first session. And sometimes Beatrix will get stuck beside the bed, and you have to push her for her to continue.

Encountered the same problem. Old Ben can't be hired. Santiago can't be hired. Fisto can only be hired once, and will go to your room after that, but will not give the continuation conversation option, instead only allowing you to demand a refund.

In my case, I recruited all four escorts before announcing that I had recruited any of them. I recruited Santiago before Old Ben, but announced that Old Ben was my choice for the position.