OKAY let's sort out the Plato/Admetus/George thing again!
This is Admetus. In the UK tradition, he's the cat who doubles as Macavity, and he usually does the pas de deux with Victoria. He also tends to be have like an older kitten, sometimes hanging out with the boy kittens and sometimes helping the adults to organise them. Him eyelash boy, with red wig (and a black spot and stripe) and reddish-brown markings all down his right side.
This is Plato. In the European, Australasian, and Broadway traditions, he did the Macavity track, but usually didn't do the pas de deux. As you can see he's based on a completely different design - in fact, in the UK tradition the same Napier design was used for Victor. Plato is an adult and mostly hangs out with Alonzo. He's usually nondescript greys and browns, often with a grey base rather than a white under his darker patches, and in the Broadway tradition he often has a square patch over his left eye.
This is... Admetus, renamed Plato for the 1998 film. (Possibly. Bryn is only credited as Macavity in the film, but it's a reasonable guess since the other two boy kittens were definitedly given their American names for the film - Pouncival and Tumblebrutus, rather than Carbuckety and Bill Bailey. In any case, he's either called Admetus or Plato, and he's the cat we're used to calling Plato in the film, so let's go with that.) Eyelash redhead baby brat boy, hello!
After the 1998 film[1], a lot of other European productions followed their example and began to use the London designs, while using the Broadway names for the boys (and sometimes Sillabub instead of Jemima). So this is Plato in the Dutch tour and the German tent tour: redhead eyelash boy!
[1] Also Zurich/Euro tour 1991–94, which followed the Vienna tradition for naming but merged the designs with the London ones.
And then of course with the revival era (c. 2014 onward), ALW etc have been trying to remove all designs except the London ones, so Oasis and the Broadway revival use the Admetus design and the Plato name. Meanwhile, other productions (UK/International tour, Vienna, Paris, Asia tours) call him Admetus.
So basically: redhead boy design is called Admetus, but sometimes gets used nowadays in productions where they call him Plato instead. George is not involved.
This is George. UK swing or minor kitten, two eye patches and a mouth patch. Never called anything but George until the Broadway and UK revivals decided to have a Carbuckety and a Pouncival, so renamed George to Pouncival and left splashy-eyepatch boy as Carbuckety.
Frank Thompson is only credited in the film as 'Rumpus Cat', but this is more or less George as he was being played in London at the time (just with the makeup redesigned a bit for the film).
The reason some fans of the film have historically used the name Admetus for George is due to Frank being credited as 'Admetus/Rumpus Cat' on the film's short-lived official website. I'm fairly sure that listing is an error: there are plenty of other errors on there, if you look carefully, and a website in 1998 was less 'official Word Of God' and more 'neat gimmick which might link customers to where they can order the DVD', so accuracy on points like minor characters' names probably wouldn't have been such a big deal.
It is possible that this was meant to be an intentional renaming of the character—or even the creation of a new character, like Femi Taylor's, based on George's design like (one of) hers is based on Cassandra. But if so, it never caught on: outside the film, there is no tradition of using the name Admetus for a George-like character. So historically, Admetus just means 'redhead eyelashes boy, who sometimes gets renamed to Plato'.
