Knowing we usually seem to avoid making pages for names not used in music works (at least relevant for this db), creating that alias of alias thing is ok, I agree.
However, he does use the real name for music overall (as seen on the homepage)
https://itunes.apple.com/jp/album/id398168862
so maybe better to make the page for the real name after all and connect the aliases just to make it easier for tracking (and leaving just 園田 智也 in absence of 智也 reading, oh and adjusting to Yuki instead of Yuuki to match that homepage again)?
edit - added the dude anyway...