Hiccup's Element Secret

This story is set after HTTYD 2 and Frozen with some changes the first Valka never went missing the second Stoick didn't die and Astrid is his sister and NOT his girlfriend. Hiccup had a secret that only him and 4 others know about, how will they, his wife to be Elsa Winter, her sister Anna along with his own sister Astrid react when they find out.