I was lucky enough to get to sit in on one of these sessions in downtown Seattle a week ago, there was a lot of material to get through in a day and it was pretty hectic. I really enjoyed the day and getting to chat with some folks there. Some questions came up that I needed to go do some further digging on, the answers for query notifications are below, the XML ones will take an extra day or so. Thanks for coming to the event and see you at the next one.
 
Query Notifications, what are the limitations on the queries that I can subscribe to:
            - Results of an SP? Yes, valid SELECT statements within sp qualify fine
            - Results of an SP that returns multiple result tables? Yes, one subscription is established per statement executed
            - Queries(what are the restrictions, same as indexed views in terms of support for outer joins etc)? Yes, same as IVs
            - Use of temp tables in an SP? No, temp tables we disallow
            - SQLCLR Procs? Not allowed
 
Oh and I have managed to get some more folks from the dev team to volunteer to come to the next days which are luckily in Bellevue, so we should have folks from the SSB, SQLCLR, XML, Express and BI teams there!