When you fight it all attacks are neutral to my knowledge. Since the battle is treated a bit like a rouge mega fight, it seems like it would have a type.
Dataminer Anubis has described Hyperrogue Ange's flowers as 5 Def, 5 Sp. Def, weightless, typeless enemies who each have 25000 HP.
The battle is also heavily scripted, in particular the flowers' attacks and the segments with Zygarde.