I want to use my email for a new game, new castle since I didn't port to my province in time. Possible..

You can start a new game at any time and move it to any province before you reach level 6. Any old game that you stop playing (abandon) will remain in place for 2 weeks. After this the castle will disappear from the state until you log in again.

I think you can reuse the email address for a new game, but if not then you can use the same address with a different capitalization. For example the game treats [email protected] as different from [email protected] but you will still get the emails to confirm the sign up.