I would identify this as such case as a NT writer using a popular reference (something most of his original audience would "get" fairly easily) for a colloquialism. The underlying Bible-story is the primary referent, the apocryphal names are technically supplied elements from a later story-teller. None in the 1C who divided between the Exodus account proper and a popular retelling would mistake the names for belonging to the inspired Hebrew text. We're reminded of the utility to hermeneutics of historical background knowledge (in this case, to Paul's letters).
If I recall, the names are Hebrew, and thus may have identified to the popular audience that (in the retelling) these men standing by Pharaoh against Moses were basically traitors to their fellow Israelites. This could have been a true supposition or inference, even without the benefit of Hebrew names; but the names solidify the idea. Paul could also have this interpretation in mind, given the warning-context of his letter.
The Christian interpreter has an extra layer to negotiate, due to the presence of the names now included in his inspired NT. He could go with the idea that these must be their actual names preserved outside Scripture until such time as the HS saw fit to confirm them for all time after a millenia-and-a-half by apostolic sanction. Or, he could regard their names as "supposed," and as placeholders bringing to mind the whole multi-chapter episode in which these (originally unnamed) men played a part. This, after all, is Paul's use of them in his letter. A man's name all by itself seldom gives us significant relevant data about his importance in the narrative.
Names are one method of realizing or historicizing a literary figure. In the story of Moses and Pharaoh, these magicians have a small supporting role behind Pharaoh. Refer to "Pharaoh's magicians," and maybe the allusion is lost on the audience. WHICH Pharaoh? There were at least two in Moses' lifetime, possibly three (birth, flight, and exodus). Assigning these magicians names (even taking names from popular culture) definitely characterizes them, lifts them off the page and stands them in front of Moses (a fully-fleshed out figure) as if to do him battle.