The pack tokens are fully on Steem, but anything in Steem Monsters is in their own database that is not on either chain.
I believe there will be an option to have your Alpha/Beta tokens on either Steem-Engine or Hive-Engine, but I am not 100% sure on that.
I hope they'll make a complete switch one day. It looks pretty bleak for every dapp trying to support both chains. Even DTube was eventually hurt by the JSteem.
I would personally feel very trapped if I was a Dapp dev on Steem trying to diversify to other blockchains..