Jade Herrera has had visions of Christopher since S2, figures in Christopher's old black book, scenes from a root cellar, the recurring symbol. The S3 finale resolved them: Jade is Christopher reincarnated.
After S4E6
Boyd took a jackhammer to the basement wall and found Jade's door, public, undeniable vindication. Jade also spent the episode trip-sitting Acosta, who is in a suicidal arc.
What's confirmed in canon
S1Arrives in Fromville the same day as Tabitha.
S2Visions of Christopher begin. Finds Christopher's notebook with the central symbol.
S3 finalePlays the lullaby. Anghkooey children appear. He remembers being Christopher.
Earlier cyclesMany identities before Christopher; an early inhabitant of the town.
Where the community lands
Reveal is canon. Open: what Christopher was doing, why Miranda hid Victor from him.
Still open
Q1What did BIW tell Christopher?
Q2Why did Miranda hide Victor, danger or victim?
Q3What does the notebook say?
Q4Who was he in earlier cycles?
Connected entities