I don't really think I need to explain this. It's a rule my fellow men should follow.
So I'm guessing the Green one with Red boots is female?
...wait, the Pea-green-red one is female, yet addressed to by the yellow-blue one as "sir"?
While "sir" is used mostly for men, it is a generic term for anyone above you in rank... or I've been watching too much Star Trek.
So have you decided these guys names?
...It's clear he's decided at least two of them...
I wonder if she was alive in the times where Meta-Knight was fighting for peace. That would be a good reason for her age.
I'd recommend "m'am" next time.