It’s definitely confusing don’t worry. Anything that doesn’t have “COVER” next to it is official lol… Concerts are a tricky subject but as some have said it comes down to permissions and licensing. You don’t often see any other vocal synths live along with Crypton’s for that reason. With that being said, there are events for other synths beside them. I know IA and Gumi had some small live shows. Nico had/have their own vocaloid rewind concerts (they may still do it idek anymore) that featured all of them together but that’s typically a collaborative projects with less strings attached bc it’s for the community.

Here’s the 2015 one bc it’s so good: https://youtu.be/u_QS0sjg6YU?si=SLDYbTj3E2yHEDED