If you use E to grab or dodge it presses the buttons for 1 frame and releases them regardless of how long you hold E, assuming you aren't already holding the buttons it uses. If you hold E at neutral it will hold ABC for as long as you hold E and the stick is in neutral. If you press any direction that isn't 5 the buttons are released.
If you hold 4a/6a and press e you'll always get an ex shield.
If you hold d and press 4/6e you'll get a 4a/6a on the first possible frame, in case you have a charged one and don't want to charge it.
If you hold a and press 2e you'll get an instant release 2b. F-moon doesn't need to hold a.
If you hold b and press 2e you'll get an instant release 2a.
If you find someone that doesn't know you can bet him that you can press and release E in 1 frame 10 times in a row.
So basically nothing you can actually use in a match that isn't already easy to do. I'm also aware of how completely useless some of the things I listed are. I listed them to be complete, and if in the future E doesn't change but someone gets a charged 2A it's covered.