Yes, likely system driven multisig. No, likely no key for you. They give you cash, you give them trust. A challenging trade in a trustless environment.

i’m not entirely sure what that solves. why would that be valuable to you? we already have no rehypothecation. we will add proof of reserves so customers can see the bitcoin. i personally don’t get why holding one key is valuable, you don’t control the funds anyways and it makes the product extremely expensive