@Avery3291
I interpret this as a parallel dimension where instead of trying to stop the Rainboom, she used a different type of time travel to kidnap Sunburst right before he got his Mark, or perhaps between that and his departure for Princess Celestia’s School for Gifted Unicorns. In the second case she might have considered that she was perfectly capable of teaching magic (which she probably is).
Doctor Whooves (AKA Time Turner) is giving chase via The Spirits of Hearth’s Warming Past, Present, and Yet To Come, having managed to render The TARDIS only able to travel to Hearth’s Warming Days. Derpy is his Companion (wife?) and her/their daughter Dinky (W)Hooves ended up getting caught up in the adventure.
Snowdrop is fulfilling the role of The Spirit of Hearth’s Warming Past (can’t who it was in the actual episode) and is a fanon Pegasus who is blind and crafted the first snowflake to make Ponies appreciate Winter, and by analogy/extension Princess Luna’s Night. She can’t SEE the stars, but apparently she can HEAR them and made the snowflake as “A star for Winter”. Because she is blind, Derpy is frantically shouting course corrections to her.
Diamond Tiara, based on other images, the one The Spirits of Hearth’s Warming were teaching a lesson to when Doctor Whooves recruited them.
Previous images in this continuity (which is a subset of the Advent Calendar pictures Irony by Exception did several years):
2017: >>1613722
2019 (2018 seems to have been skipped for this continuity?) : >>2226678
I interpret this as a parallel dimension where instead of trying to stop the Rainboom, she used a different type of time travel to kidnap Sunburst right before he got his Mark, or perhaps between that and his departure for Princess Celestia’s School for Gifted Unicorns. In the second case she might have considered that she was perfectly capable of teaching magic (which she probably is).
2017:
>>1613722
>>2226678
Edited because: Added links & realized Snowdrop is subbed in as Hearth's Warming Past.