i'll be honest, i don't see how they could do june egbert well. ignoring how bigot-y having a character whose "MAN GRIT is off the charts" transition into a transwoman feels to me, i'm not confident that the BC team can make it work.
the fact of the matter is, john is an incredibly established character. he had nearly a decade of characterization, and for all intents and purposes his arc should've already been over. without the writing team being impossibly diligent and careful, june will land somewhere between complete erasure of who "John June Zillyhoo Egbert" is as a character and completely tone-deaf and flippant.
that being said, i do think that june could work as a harry arc instead. it could be used as a way to flesh him out over the course of the new session. however, that runs into the issue of figuring out what to do with the whole john situation. there's been 6 years of build up from both a writing and a reader standpoint. it would be hard to wrap that up cleanly, and there most certainly would be backlash.
either which way, i have a feeling it's not gonna end up great in one aspect or another. i could be pleasantly surprised though, so who knows!