Would be great to see what you do with the planetary tuners! What’s your plan for the fifth string peg?
I have had this buzz you speak of, in my case it comes from the knots/string ends at the leather tailpiece, vibrating against the drumhead. I folded a piece of paper and wedged it between the tailpiece and the head. I suppose the solution with the nylon strings is tie the knots on the top side of the tailpiece or trim them close on the underside. Anyway, obviously not an issue for you now with different strings.