Hello, @danniguise,

Thanks for stopping by with your comments and questions.

I can only answer the last question. As well as I can tell from observing, Mr. Smith is using "Dropped D tuning" and is playing the piece in the key of D.

In this tuning method, all but the lowest pitch (physically on top) string are tuned to the standard values of A, D, G, B, and E. Instead of the normal 'E,' the top string is tuned to 'D.'

Although I'm no expert, I am fairly sure that is the case for this recording.

Scott Joplin and his music would be much older than Django Reinhardt, dating back to the 19th century. I don't know enough about Reinhardt, and he may have enjoyed ragtime?

For better answers, I would just suggest combing the internet. Good luck!

And, Welcome to Steemit. :D