Touhou and Undertale plays large parts in influencing Allister's design and themes?

As you guys see, Allister is an interesting character.

A silent boy with lots of mysteries, Ghost-type Trainer, one of the few game characters in the whole Pokemon series who wears a mask, very cute (keep this important!), spoopy, is a child Gym Leader, have purple clothing,...

But he also looks like as if he was inspired by Touhou and Undertale characters... Was him?

The most possible inspirations for him from the Touhou Project are Hata no Kokoro and Satori Komeiji. With Hata no Kokoro, it is obvious since Kokoro is associated with masks (like Allister), and Kokoro is almost always seen with a mask on (albeit at the side of her head, unlike Allister who wears it to cover his face). She also seems to rely on the masks to convey emotions, as her actual face is expressionless (like Allister's mask), similar to Allister who rely on his mask (s) to hide his identity. There is also a color palette of Kokoro in the fighting games that resembles Allister's hair and eye color scheme (see this image, the third one from the left). So it is possible to have Kokoro inspires Allister's design.

For Satori, there's no doubt that he and Satori are similar: Both are the 4th bosses of their respective games, both seems to live a solitary life, avoiding seeing humans, but instead seems to be connected to non-human beings, similar clothing (both wearing shirts with wide sleeves) and design (both have short hair, in some fanarts, her hair is styled similarly to Allister (without the ahoge) (see this one for example)), and short stature (Satori is sometimes depicted to have a short stature, which is comparable to that of a child or that of Allister (he's a child obviously)). Also, Allister's crest also somewhat resembles Satori's Third Eye placed on top of an enlarged version of her shirt's heart-shaped buttons. Also, both characters wear short white socks. So it is more likely for Allister to be inspired by Satori more than he being inspired by Kokoro.

For his Undertale inspirations, Chara and Asriel are most likely his other inspirations. Given that Toby Fox has worked in composing a track for SwSh, it is possible that Toby might leaked Undertale materials during his time working for The Pokemon Company just for a piece of music, and the Pokemon staff took character materials from Undertale as inspirations for Allister, or maybe due to Undertale's mass popularity all over the world, then the staff for SwSh decided to design Allister based on characters in UT.

For Chara, there are many similarities between this character and Allister: Both are human children, both have natural hair colors (albeit Allister's hair is having a bit of purple tint), both can be possessive of people around them (for Chara, this is evident as they seemingly wants to claim Frisk's SOUL for theirselves; and for Allister, this is somewhat hinted in his battle dialogue (during the Gigantamax section; as he said "You won't get away, I won't let you!" (maybe it's just for aesthetic purposes, but possibly to some fans, it might hint his actual personality)), both have short hair, and Chara's jumpscare face also somewhat similar to Allister's mask: Hollow eyes, a wide-open mouth, but for Allister, minus the blood trickling from the eyes and mouth. Also both can be judged as either creepy or cute (depending on your opinion).

For Asriel, there are two things that makes him similar to Allister: Allister's name if we remove an "l" and the "t", rearranging the remaining letters will give us "Asriel". Second, Asriel and Allister can be seen as possessive of others, the reason of this for Allister has been explained in the "Chara" section above, but for Asriel, in his battle dialogues, he don't want to let the player go, which can be considered possesive of others, until the player reveals that they are not Chara. Also both are male characters and both are children (albeit Asriel has an adult form). Asriel's ears and tuft of hair also somewhat looks like Allister's hairstyle (if we make the ears a bit shorter and make the ears have jagged edges to make it looks like hair).

Do all of these theories sound neat to you?