I have an interesting theory--well, theories--that I've been contemplating for awhile theory; what if Liana and Alexa(Barbie and the Diamond castle) were the daughters of Annaliese and Julian, and Erika and Dominick(Barbie as the princess and the Pauper)? It would explain how Liana and Alexa are so close, and also, what if Barbie and Theresa are related to liana and Alexa? Think about it--

They were singing Two Voices, One Song in the opening scene. Which is the same song Alexa and Liana sing. Maybe the song was learned by each generation of people in their family. Yes, Barbie mentioned trying a new chord for the bridge, but she could have just been tweaking it a little, instead of actually writing the song.

Also, while the events of one or both those movies are happening, the events in Fairytopia could be happening at the same time, as well as the events taking place in Flutterfield(Barbie Mariposa) with Henna and the Skeezites. and we see Elina as the narrator in the first Mariposa movie when she's telling Bibble the story, so she must have befriended Mariposa sometime in between Fairytopia: Magic of the Rainbow and Mariposa.

I also believe Flutterfield could be one of the seven regions of Fairytopia, although it's cut off from the rest of it like Elina told us. Maybe Shimmervale is, too.

I feel like it'd be really cool to see if there's a way to connect all of the Barbie films(the older ones, anyway) into one giant storyline. Let me know what you guys think in the comments :)