Thank you for this. It’s really cool to see how one would be able to leverage threshold signatures for Aztec transactions.
One nitpick is that typically multisigs refer to the policy of having distinct signatures to approve a transaction as opposed to having distinct entities who hold shares to product a signature to produce a transaction. It’s a common but important distinction because multisigs for functionality closer to what Safe allows.
With this nitpick out of the way, I think it would be fruitful to implement multisigs on Aztec as a high priority for the project. There have been attempts at privacy-preserving multisigs on Ethereum before like zkShield. The key driver for my opinion is that it would unlock privacy-preserving group management of funds in an auditable way. There are numerous examples of on-chain funds being controlled by DAOs with Safe wallets. If there’s a way to provide these DAOs with a useful form of privacy for managing their protocols, that would be a massive unlock for the Aztec ecosystem.