Yes, yes and yes but not too bad.
Once out of Anno, boat traffic lightens up and is quite manageable on Chesapeake Bay.
Holiday traffic, especially on Fri. and Mon., could be bad but it is unpredictable. The major choke points: Bay Bridge from Anno to Kent Island and the Hampton Roads Bridge-Tunnel from Hampton to Norfolk may not even be in play with the proposed race format.
Memorial Day weekend is popular but it is not full-on tourist season. Accomodations should not be a problem if made in advance.

CRAC ran a 3 stage DTB on Memorial Day weekend for many years in the 80's and 90's with great success.

Chris