Seeing these ponies in these forms inspires me with an idea. Just give me time to provide the links to the details. Also, credit for the vectors goes to the original creators.
 
Starlight and Trixie by  
Coco Pommel by  
AJ and Rara by  
Fluttershy by  
I don’t know who created the Skystar vector. Nobody else of Derpibooru knows either.  
I decided not to add Rarity because of Capper. https://www.fimfiction.net/story/388325/the-backstories-of-the-new-ones Reading this story might leave AJ and Fluttershy to be with Songbird Serenade. Also, I made this blog post on FiMFiction a while back. https://www.fimfiction.net/blog/752332/i-might-have-some-good-ideas I’ll add Coloratura and Songbird to the list. AJ and Fluttershy might join in not only because of my earlier statement of them and Songbird, but because of AJ’s childhood friendship with Rara, and Fluttershy deciding to hang out with Starlight more, dating back to S5E2. Of course, in a different way following the most recent events. With all these ponies and Skystar as seaponies, Pinkie would make an excellent member of the group. The only problem, there are now show-accurate/movie-accurate vectors of Pinkie as a Seapony. Not even perfect custom vectors of either style of Lyra, Bonbon, Minuette(Colgate), Lemon Hearts, Twinkleshine, Moondancer, OR Songbird Serenade. In case that this image is flawed, I’ll expect someone to come up with a better version of this image, and credit me for the original.
 
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