>>43552032Source to what exactly? The trainer and rival in gen 1 being canonically called Satoshi and Shigeru? Yeah, the Japanese cartridges for Red and Green. Those are your first naming options fir both of them in both games. If that doesn’t suffice, then
>>43552037 here you are. Still not satisfied, check their bulbapedia trivia pages.
As for the girl being Emiko, that’s just speculation, as she never got a canon name, but it makes sense all things considered. Unless you can think of another prominent female figure in the in original development of the first two games. Though you could also call her Leaf, as that’s how Sugimori refers to her.
