Well, first of all, Changtau2005 basically built this site; everything you see here is pretty much all his work. All the templates, the site skin, all the little quotes and the random portal, all the video players, all the CSS definitions, everything.
Second, I have not personally looked through every soundtrack, so I will take your word for it that some are incomplete/out of order. However, I've pretty much taken over the job as soundtrack person, though. I'm currently doing the Kirby: Triple Deluxe soundtrack. The resolution of the videos does not affect the sound quality whatsoever, it's set that way so that it loads faster in our music players.
And yes we do have admins, myself being one. You can find a list here: Special:ListUsers/sysop NerdyBoutKirby and I are the current active admins; however Changtau2005 can usually be contacted quite easily.
The music players themselves work directly with YouTube playlists, so, theoretically, any playlist would work. Though this becomes subject to link rot, so we like to keep them all in one channel. However this also removes a bit of the community aspect, but at the same time we don't want just anyone to have access to editing the soundtracks. So hopefully we can figure out something with this.
Thank you!