>>57642692Some dead things allegedly reincarnate into Pokemon, yeah, but Ghost Types themselves aren't deceased. They're just as living as any other Pokemon, and can die all the same.
For example, GameFreak and the Pokemon Company greenlit the anime's decision to include a shiny Mimikyu who's ACTUALLY dead that Acerola is friends with.
Yes, the anime's characterizations and narratives aren't canon continuity to the games, but Masuda has said that all depictions of Pokemon share the same fundamental world with each other, and GF and TPC regularly meet up with OLM to oversee what they're creating and writing, in order to ensure the anime is not depicting false information that goes against what they believe is right for the Pokemon world and the franchise at large. Thus, it's entirely plausible that a deceased Ghost Type could exist in the games, if they wanted to depict one.