OH HMM i'm super interested in having him learn some stuff but jade would have been good at covering his tracks, yeah. If he explores deep into the Old City he could come across remnants of Jade's old lab? Jade's been careful to wreck the structure the best he can but there would definitely be remnants of machines that are clearly from the Union instead of being old tech

and possibly an irregularly large amount of Pokemon bones scattered around oops (depending on when Robotnik finds the place)

I'm pretty flexible with this so let me know if you have any ideas :|b

and YES cr between the two of them would be fabulous! I'd love to have them work together at some stage if more group plots come up