while i don't think this was the intention at all, i feel like january johnson/ian jacobs are incredibly plural coded. probably median system, and probably some type of adaptive, though i don't know the nuances of those enough to tell which type.
at first, he was just the one person. and technically he always still is, he's not lying when he admits that he's the mayor. but you can definitely tell that his mannerisms change. ian is more put together. they speak differently. and maybe it's just acting- or at least, part acting, part embellishing the truth- at the start it probably was.
but he compartmentalised really well. a bit too well. and these two 'masks' developed into facets, one that can hate the mayor and one that can be the mayor.
i'm somewhat speaking from experience as a system, though we're more differentiated than we headcanon January and Ian. but it's also not just us, we asked a singlet friend a while ago and they agreed he's kinda plural coded.