When putting a skin in that magic box for your taikomap (or even your standard map and you try to play it as a convert) it won't be used no matter what you try unless it is called "taiko".
As far as I am aware this does work for standard at least and maybe also for the other modes but I didn't test this.
I confirmed this in #modhelp with blissfulyoshi, the preferred skin was definitely available.
Use Taikoskin and ignore beatmap skin were both unchecked.
Video or screenshot showing the problem:
Hard to show, just try it yourself.Dntm8kmeeatu Edit: 6/4/2017
Not only does the name have to be specifically "Taiko" It also just doesn't use half the skin elements. Even though they exist and are packaged with the map, they are just not used correctly when being used as the beatmap skin.
osu! version: 20170404.2 (latest)