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I’m just going to leave this early concept art of Alphabittle here…

BetaAlphabittle (or BetaBittle) on the top, bears some resemblance to Misty, his early 3D design also had a very similar color scheme to her. Thus I assume that the (main) reason why they’ve changed Alphabittle’s design was because the resemblance was way too obvious.

What I’m trying to imply here is that I’m almost sure that the production of Make Your Mark is going way back to the production of ANG. I think they’ve already set its major plot points, characters and their relations, dynamics, etc. back then.

Even though it’s also possible that they’ve simply made the New Generation movie open enough for a future serialization (Make Your Mark), but considering that there are some hints for future plot points (such as AlphaHaven dynamics build-up) even in the earlier storyboards, when Alphabittle was this quirky, blind sage-type of a character, I’d rather fo with the idea of ANG and MYM were written fairly simultaneously, well, at least as far as their major plot points go. I mean, you can even see Opaline’s cutie mark in the movie, so the writers probably planned things way ahead.

“====”:https://derpibooru.org/images/2983633

And if Opaline’s kinda referenced in ANG, I think it’s safe to assume that the movie was written with Misty’s future inclusion in mind.