1. will Aware then allow the use of GUID for the ID now - sounds like it is?
No, it will not use GUID, it will use database sequences to generate ID's (see CREATE SEQUENCE command in SQL Server or Oracle)
2. Will the handling of "External Databases" change with the the database sequence change?
No
3. I do not see anything regarding possible built in handling of run-time attribute properties change via code in the rules or something like that - or maybe it might be part of "More..."
We are still thinking on how to do this - it's not easy. Maybe it will be part of "More..."