Questions after first play

Hey there,

A few question after our first run :
- Do Alien monster free smash action, requiries them to roll or is the door automaticaly broken ?

- Are Ghost monster really trapped by bear trap ? 

- Does bear trap prevent Monster from being pushed as well ? Or blinded by the Flood light ?

- If you smash a door leading to a room which already had another door smashed, do you shuffle the room deck as well ?

- Since ghost can go through wall, they do not smash door, so they the victim has no time to hide and will be first card on top of deck ?

- Does the special Crittlin action of adding an extra Crittlin in the room work on crittlin already in game ?
Does this action also tap the crittlin being added ?

- How are barricade built ?

Thanks for your insight