Hmm, good question.
As far as I know, everything will just be copied over as it is now so you will have the same username over on Hive.
The PAL Discord server has a load of knowledgeable people and the developers of the platform if you wanted to ask in there - here's a link to the Discord
I have a feeling you may have to start a new account with a different username if you wanted to lose the "steem" part of it but as it is a new platform, I'd like to think they can be flexible in the transition... I'll keep my fingers crossed you get the right answer 🤞