far left - first entering into equestria as a pony
second - ascending to alicorn of hope after shattering her horn at the end of the intended arc of Mirror of Worlds (https://www.fimfiction.net/story/282966/lost-in-the-mirror-of-worlds - cancelled story)
third - Dawn’s form without alterations or changeling abilities by around ch 22ish in Soldier and Hope (https://www.fimfiction.net/story/411874/the-soldier-and-hope - ongoing story.)
fourth/last/far right - projected future of fully grown Meadow Dawn, queen of the sunrise hive.