Thank you for taking the time to write this up @0xTaiga, really appreciate it. I think it makes sense for the community to evaluate both proposals and see which one would be preferable for a pilot programme (or perhaps test both protocols in practice).
The advantage of Vendor to me seems that it was already designed with Olympus in mind initially and that it is audited and used successfully in practice - i.e. the contracts are already (somewhat) battle tested on the Arbitrum deployment. If the community would like to proceed with a "clearing house" solution I would be in favour of using Vendor as well, considering the history between both protocols.