Hey @skywalkersv, this is a great idea! I think hooking them up just requires a bit of tinkering. Just to be clear are you using the GoPiGo2? The Arduino can definitely control the GoPiGo2 over I2C, and you could easily adapt the C libraries we have that run on the Raspberry Pi.
As for the Vex, you may need to do a little research on whether the Vex can be programmed with I2C. Do you know if it can?