Damn we need more ragtime in the fandom.
Utilize the octaves in the left hand! Look at the music sheet for "Maple Leaf Rag". That might get you closer to the ragtime fill. And when you move the off-beat chord closer to the bass notes, your right hand is then free to do other things. Like cheesy chord arpeggios. Also on the off-beat strings at 0:52 specifically. I feel like you can put a bit of non-chord tones in there. See what happens if you just make it play some different notes. A seventh, maybe. Ninths are sexy, and of course used in ragtime.
Articulation on the fiddle you might want to fix, but that will be down to how good the library/sample is.
Keep up the effort!