Those with the most votes will control multisig keys on Bitcoin and wherever else.
My understanding is that the BTC will actually remain solely in the hands of the wrapper because any attempt to lock it up with multisig will lead you down the crazy path of Lighting where each channel is a two party multisig amount of bitcoin.
That is a main chain transaction to put BTC in to Lightning and another to take it out: VSC will have this.
But on Lightning that BTC is ONLY useable by two parties shuffling it back and forwards. This is the critical design problem with Lightning: it is inherently between two fixed points and those points have to be servers. All the added complexity exists because you need routing nodes to forward other people's transfers.
A Hive backed system allows point to point transfer: you can replace custodial Lightning Wallets AND full bitcoin nodes on servers running 24x7 with Hive accounts!
@vaultec kinda said this but I hope my explanation helps.
So the idea here is that the BTC remains technically at risk of being absconded with by the wrapper, but in return the wrapper has staked HBD or Hive or some other collateral which is held in a non BTC multisig and can be slashed if the wrapper fails to honor a commitment in some way.