Since the canon endings have been revealed... does it mean this is now an alternate timeline? O:

Pretty much! We always knew that there would some day be a canon Epilogue (which is still in the works, as far as I know), and that whatever we made was unlikely to slot neatly into place with that content. Act 8 was intended from day 1 to diverge from the canon timeline post-Act 7.

I think this feels in keeping with the Homestuck narrative being game-based. Every team making a fan continuation from Act 7 is just unlocking an alternate ending for us all :o)