>>41848867>I don't think the ones that changed had any real reason to change either, they just did.They actually do, if you stop and think. The only Pokemon that had a type outright replaced were Normal-type, with the sole exception of Mega Altaria.
>Fairy is strongly tied to the moonEvery Normal-type that evolved via Moon Stone became Fairy-type. Also, Clefairy's line is strong tied to the moon.
>Pokemon in the Fairy egg groupTogepi's line, Snubbull's line, Mawile, and Cottonee's line.
>Snubbul's lineThis additionally is a pun; it's a fairy dog.
>Mawile, Ralts' line, Cottonee's lineMawile is based on the futakuchi-onna, a yōkai, which are more akin to strange spirits than monsters. Ralts' line has an otherworldly vibe to it in general. Whimsicott specifically is said to be a trickster that does things like moving furniture, and leaving cotton balls everywhere. These three things (spirit, otherworldly, trickster) are all things attributed to the fae, or fair folk.
>Mr. MimeMr. Mime is just weird in general.
>Mega AltariaFor this, I think they just wanted something unique for Altaria's Mega Evolution. They could have kept it Dragon/Flying, but that would both be boring and make it too similar to Mega Salamence.