I'm trying to reproduce the script some NPC in vanilla FNV are using to remove all weapon (temporary) from player but i'd like to also remove the armor/weapon from both the player and his/her follower. Is it possible to apply this effect to the follower as well?

Take a look at TopsFriskingHoldoutTriggerScript as an example of how to do weapons for the player and two followers. It wouldn't be too difficult to add armor. To get the ref of custom followers, you could use GetActionRef as they go through the trigger http://geck.gamesas.com/index.php/GetActionRef, then test the ActorRef with ActorRef.GetPlayerTeammate http://geck.gamesas.com/index.php/GetPlayerTeammate