This article describes the personifications of Pokémon on pixiv. For more information on tags, please refer to the Pokemon Mimic page.
Pokémon personification (ポケモン擬人化, Pokemon hanken gijinka) mainly refers to Pokémon that are completely human in appearance without retaining their original form, and wear clothing and ornaments that resemble the original Pokémon (so-called moe personification).
In rare cases, some Pokémon retain their original form but assume human-like heads and gestures (so-called furries, beasts, anthropomorphism).
Naturally, there are no rules for personifications, so you can draw them as you like.
Therefore, whenever you draw and publish anthropomorphic Pokémon illustrations, you must be aware in advance that there are many diverse ideas and many diverse points of view among fans.
In the first place, it might be a good idea to write a clear explanation of whether it is a cosplay or an illustration of the Pokémon's personified form.
Incidentally, there are also derivative works that are sometimes seen personified on the official side, but they are completely unrelated to the derivative works on both sides.