>>5182424You are right that it hasn't been directly covered. I am actually pretty intentionally vague about which OG cast members know, and how much they know, concerning the events of 421.
Here's what you could infer from what I've written:
By the end of the OVA (which concludes with Whitney and Ally at senior prom), there's no clear indication that Whitney knows about 421. Likely at this point she still doesn't know. Cerise also doesn't seem to know anything by the end of the OVA.
In the bonus lewd "Plap," which takes place a year or two after Alabaster graduates from high school, Cerise directly mentions 421/422 in a phone call and shows a pretty clear understanding of what everything means. So we can conclude Alabaster told Cerise during that interim. And I have to imagine he would have broken the news to Whitney around the same time frame.
For certain by the time we pick up at the beginning of WBA, Whitney has known about it for many years, and judging by her behavior she seems to accept the truth of the story.
