1. No, you don't need to put information in custom podcast channels but in the category podcasting area.
2. On blubrry, just add show #2 to your main account (click on "add program" in the "manage account area") Then go to that "program" and setup stats. You would put that redirect URL in the Category podcasting area under "other settings" .. Do that with both shows.. Each with their own redirect keyword.
3. To add your podtrac redirect into the mix, put it like this:
http://your_podtrac_redirect/media.blubrry.com/your_key_word/ That way it will do both redirects. A safer (but not as nice) way to do it is to manually put both redirects like that in the Media URL area of the post template. At least the first time just to make sure it validates that way. You may have to change the order of the redirects.
Hope this helps!
-Mike