No. Your email will continue to be of the format firstname.lastname@example.org.
Yes, any data stored on the Exchange server will be automatically migrated for you by OIT staff. If you have offline archives (.pst files) that you would like to have migrated, please open a support request with the IT HelpDesk and we will be happy to assist you in importing this data into Gmail.
Yes, two open forums will be available: Monday, August 17th in CAMP172 from 9:00am to 11:00am and Wednesday, August 19th in New Snell 241 from 1:30pm - 3:30pm. Additional sessions will be scheduled and announced closer to the September 21st cut-over date.