After much digging through old Japanese websites, I've finally found the main Touhou cast for The Sims 1. As such, here are the links for the skins I've found.
http://www5d.biglobe.ne.jp/~utapuchi/sim/dl_skin.html
Contains downloads for every Windows-era character from EoSD to MoF.
http://marionetteostens.web.fc2.com/download/skins.html
Contains downloads for a few print-work characters (Renko, Maribel, Rinnosuke, Akyuu) as well as a few PC-98 characters (Elis, Sariel, Chiyuri, Yumemi)
http://snowlady02.blog123.fc2.com/category64-1.html
Contains numerous downloads for both PC-98 characters as well as Windows-era characters, from Meira and Mima all the way up to Byakuren and the Mischievous Fairies.
So that means you should be able to play as characters from HRtP all the way up to UFO. Not every PC-98 character has a skin, as these links are still missing several characters from HRtP, SoEW, and PoDD, but every character from LLS to UFO is available to play as.