UPDATE: JB Weld is set, seems to be holding nicely. The tube itself is not obstructed -- I can blow into it freely.

I have some pix, I just need to get them up in the cloud somewhere. I'll post them when I can. It ain't pretty, but it should be perfectly functional.
We de-greased the hell out of it. Between that and the tiny little flange we put on, it looks like the JB had ample purchase on the aluminum.
The plan now is to let the JB cure for the rest of the day. We'll figure out a time this week for my buddy (the guy who actually knows what he's doing) to come back over and help reassemble.
--Jaeger