This is cool. EdTech is undergoing unprecedented digital transformation right now. Anecdotally I can say the more personal the video interaction, the more instructive. And meshing one-on-one live video with live pair programming will be the holy grail ;)

On the coding side, I've had more success using P5JS than block-based and visual environments like Scratch. I think the great thing is that students can then advance on their own. Diving right into the API reference, The Nature of Code textbook and The Coding Train YouTube tutorials using state of the art AI techniques.

For live interactive video I use Twilio and WebRTC. But will also be experimenting with Mux soon. Best of luck!