Pichu cosplayer? Do you mean Mamitasu?
Because the cosplayer with cat's face is one of her cats called Mamitasu.
Shokotan portrayed her cats. Here is a one of her drawing:
Mamitsu is the one who is in the center of this pic.
I finally found the angela presents Nakagawa Shoko single. I uploaded in her discography.
I also uploaded the Tokyo Shoko Land concert.