Yes, but quorom isnt a rule tied to the treaty specifically, it's a rule for how all legislative bodies work

It's not so much that the nato treaty required quorum, it's that any/most legislatures require a certain amount of members present in able to hold a vote. Imagine if you only needed one guy to show up to be able to hold a vote, there could be a lot of shenanigans

Sweden is not officially in untill all member states ratify their ascention. So currently Sweden is not in

That's the unabomber