I highly doubt so, as Heavenly Host likely doesn't follow the same conventional laws as Earth does. Besides, Sachiko is effectively the administrator of Heavenly Host and would have no reason or motive to give the ghosts such glaring weaknesses, considering her purpose is to exact revenge on those who wronged her.
Sachiko died due to an attempted rape attempt where she was unable to defend herself, so she would logically be overwhelmingly strong in a plane of reality fabricated by her desires of vengeance. Keep in mind though, that
the gang found a way to directly engage and defeat Sachiko in combat at the end of the original PC-98 game. So perhaps the ghosts are immune to conventional weaponry and fisticuffs, but not entirely invulnerable.
3DS Friend Code: 3179-6117-3933 | PSN: ansonip2000 | Steam: Kneekicker
Official Take-Mikazuchi of the Shin Megami Tensei IV board.