Well, as far as "teenagers acting like children" . . . . my dad was 64 when he passed away, and would act like a 2 year old on occasion up until his death. Age itself, has nothing to do with a state of mind.
I'm not sure if they have trust issues but they have been mistreated to the point of thinking they only have each other... But once u met someone that treats u good and is under the same conditions as u.. Won't u try to trust them since u imagine that they will understand ur prblm.. But keep in mind they are still teens and not all teens have a strong state of mind... If u been mistreated so much and a good person shows up won't u try to depend on them...
So, I really like the plot idea but let's be realistic. They are supposed to be teenagers not kids. They act like children, very naively. Even if we can clearly see the trust issues they are not suppose to trust anyone easily (as we can see with there family) so I didn't really understand why they trusted the butler, like he's kinda of a random guy that was recommended by the sus duke sooooo yeah. But apart from that I really like the story .