"Frozen heart" foreshadowed the entire movie and was about Elsa. She's beautiful, Powerful, Dangerous and Cold. I think the foreshadowing was about both Elsa Hans. Elsa had actual ice powers, but Hans had the frozen heart.
Also, Anna had waited literally years to see her sister again. To connect with her and have the love that they used to share. Now, in this moment, she gets that. She is reunited with the Elsa she knows.
"You ever notice how Max, Prince Eric’s dog from The Little Mermaid, kind of knows what is going on more than Prince Eric does? He’s pretty observant for a dog." Thats why I hate prince Eric. His dog is smarter -- Kind of like Alistair.