I'm sure the word is ubiquitous; however, I'm not convinced that Equinox in this context necessarily relates to the drone, which I assume will turn out to be innocuous.
I dunno, it seemed pretty nocuous to me. (Which, believe it or not, is an actual word. I know -- it surprised me too.)
And my point was that their reason for using "Equinox" was probably more "This sounds generally cool and ominous and mysterious" or "This is meant by its namers to usher in some important transition analogous to the changing of the seasons" than "This will thrill the five people in the world who remember that there's a Marvel character named Equinox." Not everything is an Easter egg.
Perhaps it belongs to David's real dad. Which makes me wonder, can they afford Patrick Stewart as a guest star?
I think I read a quote from the showrunner saying that the second season wouldn't address the issue of David's father directly, that there are other things to focus on before maybe getting to that in a later season.