If therIn a fire how hard do you need to hold onto the handle to pull it down in a fire? In the 80s was it harder to pull the alarm handle because there was no ADA law? Do you first pull the handle out and the pull it down? If there was a glass rod that needed to be broken how would you know before to pull it harder? Would a person pull it the first time and the alarm did not go off so they would need to pull ti again? How do you break those glass rods with the handle do you need to pull it down and after it breaks let the handle go and pull it again? What do you fell when the handle is going down in your arm? Do you feel the handle going down when you pull it? Do people pull it with their dominant hand?
I know you don't want to hear it, but your characters sound a LOT like Twilight Characters, mostly because of the second reason. Reason number would sound less 'Twilighty' if you strictly made their temperatures whatever the temperature outside is. Reason number two could possibly change to just their eyes or hair shimmering. Reason number three is fine! Lot's of characters have super speed and strength, not just Twilight ones. Don't worry! Sounds like a cool character/story concept. Have fun writing :)
Why not ask Kiddie themselves how old your 5T is:
