I apologize for the long delay in getting a response posted for the questions that were asked during the TechNet Event in Phoenix at the end of August!!!  Thank you very much for your patience. 

1. There is no Transaction Log Viewer for SQL 2000 / 2005 from Microsoft.
2. There is no connection limit in SQL 2005 Express Edition as there was in MSDE 2000.
3. Yes, SQL Express 2005 and MSDE 2000 can co-exist on the same machine (unless something changes between now and the final release).
4. I had already answered in the original post.