piechart legend/label enhancement

Would it be possible to add these features I added here (pie label background, bounding rect and custom legend using name, ratio and value):

https://jsfiddle.net/gothmogg/zhep4s0r/

to the piecharts manually "onrendered"?

Is there a smarter and less "costly" way to have this features using C3? Maybe editing c3.js?

This solution does NOT work if the chart is minimized when loading because then the "onredendered" seems not to be fired

p.s. feel free to use anything of this code as you like.