They already are known as both Internecivus Raptus and Xenomorphs, we don't need a fan made name when there are oficial names
Internecivus raptus is a prime example of both not having any idea how binomial nomenclature is supposed to work and not doing proper research. First off, the genus name must be a noun, not an adjective. Secondly, raptus does not translate to "thief/plunderer" as it's stated; it's either a participle meaning "snatched" or a noun meaning "snatching". If you want "thief/plunderer" in Latin, you should use raptor.
And before anyone brings it up, Linguafoeda acheronsis is only marginally better than I. raptus. The genus name does not follow the typical approach to combining an adjective with a noun to form a single word in Latin; it should be adjective first, with the ending omitted in favor of the interfix -i- (i.e. foedilingua). But more importantly, acheronsis is the wrong way of deriving a geographic epithet for taxonomic purposes from the name Acheron; the suffix one is supposed to use is -ensis, thus the result should be acheronensis.
Personally, I prefer to use Xenoraptor foedilingua "foul-tongued strange plunderer" as the scientific name of the Xenomorph species, with "Xenomorph" (capitalized to distinguish it from "xenomorph" as a generic formal term for alien life) being the common name that was adopted due to the species spending well over a century being only known as "Xenomorph XX121", and many people opting to simply refer to them as "Xenomorph" or "Xeno" for convenience.