Translation:I am standing between the two women, who are wearing short skirts.
Hungarian doesn't like using the plural a lot. In this case here, each of the women is wearing a single skirt, so it's written in singular. If you said "amelyeken szoknyák vannak" instead, Hungarians would assume that they are wearing multiple skirts. Maybe layered for fashion reasons.
Amelyikeken/amelyeken seems to be plural though, although neither nő nor szoknya nor van nor allok is.
Yeah, in this sentence it would be technically (more) correct to use amelyik, since the noun nő is singular. So amelyikeken is even doubly wrong here. :´)
But it's also alright to use the plural amelyek, since you're talking about multiple women.
So amelyik has more leeway in the plural use than verbs?
I am pretty sure "sok fiú és sok lány jár az iskolaba" is also talking about two groups of multiple people and (I am now again unsure if) we would anyway use singular?
Hungarian has a preference for using the singular form wherever possible. So both "Sok fiú és sok lány jár" and "az a két nő, amelyik" are the preferred versions. But the pluralised versions "Sok fiú és sok lány járnak" and "az a két nő, amelyek" are used occasionally as well (but not "Sok fiú járnak"!), especially if the pluralised word is a bit father away from the referred noun. I'm not sure if it's grammatical, though, so to be on the safe side, I'd recommend to stick with the singular.
Amelyek is the correct plural form of amelyik. Amelyikek is also often used colloquially but it's incorrect.
Awkward situation to find oneself in. Doesn't that technically mean the speaker is wearing the skirt too since he/she is between them? (I'm referring to the English translation)
You would get that meaning if you used 'among', but 'between' just refers to the position.
Can, but doesn't have to. There's a small difference between amelyik and aki when referring to a person: amelyik singles them out while aki gives additional info:
- az a nő, amelyik piros ruhában van - the woman is specified by wearing a red dress. Meaning, she's the only one wearing a red dress and you can single her out with that
- az a nő, aki piros ruhában van - the woman is mentioned, and she's wearing a red dress, by the way
Also amelyiken or akin would be better in the original sentence, since the noun that's referred to - nő - is singular.