I’m questioning whether or not the next state of affairs is feasible. Any assist could be very appreciated.

Alice and Bob are making a (taproot) 2-of-2 multisig collectively. They don’t belief one another. They intend to fund the multisig tackle with 1 BTC every however earlier than they ship their Bitcoin to the multisig tackle, they presign a transaction (the redeem transaction) that spends 1 BTC again from the multisig to every of them. Solely when each of them have a duplicate of this unbroadcasted transaction, will they proceed to fund the multisig.

Is that this doable? So as to presign the redeem transaction they would want to know the TXID of the outputs they intend to ship to the multisig, right? In order that they would want to create their separate funding transactions that go into the multisig and share the TXID with one another (however don’t broadcast it but). Then they assemble and signal the redeem transaction. Then they broadcast the funding transactions. Is that this doable or am I considering too sophisticated?

Additionally, what if the payment atmosphere adjustments throughout this course of and one of many funding transactions doesn’t get confirmed? Then the presigned redeem transaction is nugatory since utilizing RBF on the funding transaction would change the TXID and thus invalidate the presigned redeem transaction? Is there a approach to circumvent that?

Thanks lots!

EDIT: Right here is an instance of a state of affairs that describes what I wish to obtain. Alice and Bob wish to create a enterprise fund. They have no idea by which startup to take a position simply but. After all, they are going to solely spend money on a startup if each agree that it’s a good funding. In order that they create a 2-of-2 multisig for this goal. Earlier than funding it, nonetheless, they consider what would occur if the opposite social gathering disappears or if they won’t come to an settlement about the place to take a position. They might block the others funds indefinitely. Due to this fact they wish to must choice to exit the multisig unliterally to predefined addresses.