“did you brought the documents from the institute?”  
Yeah, the HTTYD feel probably comes from the (IMO) cheap designed dragon characters, or rather, simplistic and childish. Only Ember is acceptable, Garble (though not new) and Torch are pasable.  
I mean, all of this compared to the more classically designed, even smaug-esque S1 dragons.  
The theme of the wimpy little boy gaining the big shiny at the end is a bit too common trope, specially in children toons, to make a connection with the movie; same for the “delicate little princess” proving herself to her father, they may or may have not gotten inspiration from them, but it’s merely coincidential.

@Magma-Fox  
And, if the episode’s title counts as anything, a little pinch of Harry Potter.

@Joshua  
Mulan and LOTR, TT and ROTK.

@Bardic_Knowledge  
Well, actually Dragon Lord Torch has a resemblance to the Alpha Dragon of HTTYD2.

Actually the music really caught my ear in the episode, it definitely had some sort of reference to HTTYD

I was really hoping that one of the dragonlord aspirants was going to resemble an HTTYD dragon. Particularlyl Toothless, but I wasn’t going to be picky.

A joke I missed
 
 
I didn’t get it

@Power-Up&Sky-Blue  
Well, okay, maybe the episode references HTTYD AND Mulan.

@Joshua  
I was talking to Hiccup Ember.  
I am also not sure what movie you’re referring to.  
Mulan maybe?

@Power-Up&Sky-Blue  
It’s a reference to the actual movie. In the episode, Ember disguises herself as an anonymous dragon and participated in the challenge despite Torch refusing to let her go. Recognize THAT in any movie?

You make it sound like Torch didn’t get the child he wanted.

Anything with alot of mid-size dragons gives a vibe of that franchise.
 
Incidentally, one of my favorite jokes in the first one.