They are all charged the same. Its appropriate for all of them.
They all played roles, but their level of responsibility differs. The armorer failed to do her job, but she didn’t pull the trigger. She can only be charged within the sphere of the consequences of her failing to do her job. Baldwin can’t be charged with negligence, because he didn’t prep the gun. But he can be charged with an offense for not checking the gun and for pulling the trigger.