I do not have an exhaustive answer but I do have a partial answer: all of these toys use the same sound chip, called HK628, currently made by a Taiwanese electronics company, Honsitak.

I wish I knew more context on any part of the story, but that may give you a starting point. I don't know if toy manufacturers internationally just bulk ordered those chips, if they copied the design, if Honsitak was the original manufacturer or bought it (the about page on their site says they were founded in the 90s, the chip is obviously older). I don't know if it was the first and became a default that way, or if it was seen as innovative and in-demand, or if a major toy manufacturer already had a deal in place with the chip maker, etc.