Re: Auxiliary hatch
Check out the Shuttle Press Kit here. On Page 30 is a photo of the Spacehab assembly being lowered into the bay. I see no auxiliary hatch off the tunnel on this particular configuration.
However, I have seen diagrams of Spacehab assemblies that do indeed have an auxiliary hatch at this point, like the one below:
Another shot of a configuration that appears to have an auxiliary hatch:
