Kirk here with information about tomorrow’s festival with I’ve used ChatGPT to translate from the following web page:
https://fujisakigu.or.jp/reitaisai/info/
神幸式ー随兵行列 飾馬（60頭） Shinkoshiki - Retinue Procession with 60 Decorated Horses
午前2時 朝御食祭 2:00 AM - Morning Meal Ceremony
午前6時 本宮 御発輦 6:00 AM - Departure from the Main Shrine
午前8時30分 御旅所 御着輦 8:30 AM - Arrival at the Otabisho (temporary resting place for the deity)
午前9時 御能（於御旅所） 9:00 AM - Noh Performance (at the Otabisho)
午後2時 御旅所 御発輦 2:00 PM - Departure from the Otabisho
午後4時 本宮 御還幸 御還幸祭併せて夕御食祭 4:00 PM - Return to the Main Shrine and Evening Meal Ceremony
終日 奉納挿花 ー熊本いけばな芸術協会ー（廻廊） All Day - Dedication of Flower Arrangements by the Kumamoto Ikebana Art Association (Corridor)
I don’t know if there’s anything to see at 2AM but if you plan to observe the festivities, I highly recommend being there for the start of the parade a 6AM. If you can get to the shrine (Fujisaki Hachiman-gu) a little before 6AM you should be able to see where people are lining up to view. If I can get around to it, I’d like to post a map of the route so you can choose a spot farther away from the starting point (the shrine) if you like. But, it’s going to be really hot tomorrow so that’s one reason (in addition to others) that I strongly recommend getting there early.