Pokémon the Series: The Beginning episodes covered: 210 - Holiday Hi-Jynx & 211 - Snow Way Out. For some info on the history and impact of blackface minstrelsy, you can check out:

https://www.pbs.org/wgbh/americanexperience/features/foster-blackface-minstrelsy/

https://www.theatlantic.com/entertainment/archive/2019/02/legacy-blackface-ralph-northam-didnt-understand/582733/

https://www.cnn.com/2019/02/02/us ...