We’ve also have been looking into multi round commitment scheme, but wanted to align the UX so that it would work like to musig for users. Discussion on it is scattered, for instance
Nothing got as far as your version though.
So Concept ACK from Blockchain Commons. Less clear on your specifics though. We will review.
Note that we are releasing a descriptor & multisig centric iOS and Android reference wallet soon so solving this correctly and having interoperability with others is very important for our roadmap.
— Christopher Allen