Meta that isn't fiction doesn't fill an assignment (you might be able to get away with it under the rule about poetry/if/other odd formats if they're OK'd in the letter, you might not, but definitely not if there's nothing about it in the details/letter.)

You might be able to get away with in-universe meta (i.e. ecology of vampires as written as an essay by a local scientist) for a worldbuilding request, and you could probably do it as a Madness treat if it wasn't DNW'd, but otherwise, no.