Hey! Happy to hear that you like blackwallet that much!
You cannot directly link an email to your accountid for now, I will edit this in the next update.
Now check "yes, link my email" and claim the funds
It should works!
When you merge an account, both accounts keep their federated name - it can't be edited or removed.
Regarding the email, well I have no thought about that yet but I may create a system to remove the federated email so it is free again!