basically the darkness cant infect inanimate objects like it does to things that are alive

so things like machinery would be hard for it to fully infect

so bonnie and chica still being conscious while being clearly massively infected would be an accurate way on how the darkness would infect animatronics

the darkness may be a universe buster of an entity but it still has to obey that worlds rules so infection would be slower on the animatronics

there will be a phew exceptions

for example the arcade versions of the characters would be infected instantly but not be able to leave the arcade unless something forcefully drags the character out of the arcade into another universe

instead infected versions of their faces will be displayed on the screen with tentacles growing out of it for it to be able to attack

the same counts for the many cartoon versions of the characters

now onto animatronics

i do think the darkness is able to infect remnant becouse when the darkness infects stuff it basically controls their bodies like puppets on strings wich means the darkness can control souls ( evidence from how finn looked in pibby apocalypse )

so in order to infect the animatronics the darkness has to reach the remnant not the animatronic suit

so yeah if your character is a spirit trapped inside of an animatronic suit you are in luck becouse the darkness almost doesnt work on you

but you are still contagious so if any survivors see you they will still kill you on sight