Seems like a needless worry. Even if it was the same as the Aylesbury ritual... it failed. This means there still needs to be some culmination of the loose hints. Either through a True Arc route in remake or it's all dropping breadcrumbs for Tsuki 2 where someone else picks up Roa's objective. Personally, despite the similarites, I'm not convinced what the heretic is doing is the same as what was supposed to be the T2 ritual. The guest list in France doesn't seem like it checks out. Even if it turns out to be the same, there is really nothing stopping Nasu from reworking the scenario and confrontation with Alt.