^ Imho that's highly unlikely. Looks like most CPK himejins got into it precisely because it's yuri, making this a "preaching to the choir" kind of situation.
Touhou in contrast (or it's western quasi-equivalent Undertale) has a vast and sprawling fanbase covering every thinkable niche, which abets migration between sub-fandoms to and fro femslash. E.g. you could probably consume Touhou horror media centred on Koishi as a full time job without ever running out of it, but eventually you'll encounter Koishi x Flandre and bam, you just earned your yuri goggles.
CPK on the other hand has like 10 named characters, half of which get less lines than I am making you read right now, and the overall potential for non-romantic fanworks is low. Heck, look at KPop Demon Hunters (which catapulted polyyuri into the AO3 Top 15); it's very likely that movie got more artists into yuri than CPK.
Also, the Touhou thing is true at least for Nakatani Nio. Though I think there are also plenty of artists who started out with PreCure and other Mahou Shoujo.