I just have one question about Taproot branches:
When you're making a witness stack, the public keys for the other cosigners don't need to be on the stack? [that's really the only way I see the keys being hidden, unless I'm missing something here.]
Yes, you can easily hide public keys that are their exposure is not strictly necessary:
For 1 of n signatures, unlike legacy Bitcoin script, using MAST, you will have n identical leafs such as <pubkey-i> OP_CHECKSIG for each pubkey. for claiming funds our what you are interested in (proving to be relevant), holders of each key should include log
2n hashes (Merkle path) and only their own publik key, besides the signature as witness.