One thing I'm still unsure about is weather to have my characters carry weapons or if they simply just have to dodge the enemies and stay out of sight when they come past.
My favourite room idea is number 3 as I like the idea of the different levels within that one room, enabling the player to use multiple characters as well as their abilities. Parts like the x2 player areas would be higher to access and not as simple as a balcony to just 'hiccup' over.
I thought that areas like the corridor maybe have possessed plants breaking through the window or have vegetables patrolling (something's always there. It maybe not happen straightaway but something will be possessed.)