So I've been trying to get the newish side quest thing, Panty Fairy, to work and have it installed in a fresh copy of RX10.1 where this is the only thing I have added. I did not see any listed conflicting mod in RX10.1, but I cannot find the icon to even start the thing near the infirmary as the walkthrough suggests.
EDIT: Cheat unlocks in the plugin options work, so I can get the powers, but with no events that are supposed to be triggerable in the men's bathroom at certain PC H bar levels, no added character, and no introduction event near the infirmary.
Well, I at least got it to work on the included save in BRExtras, but for some reason, it will not trigger on a new game.
Also, note that ANY game that is going with a class that is into the extended roster size, that's more than 38, will be extremely challenging if not impossible to do the Panty Fairy quest with, specifically the second or third parts as those are the ones where you have to go into the locker room on the second and have the option of doing this on the third. Part of the quest has you going into the locker room to steal freshly removed panties. I had a hard enough time with just 18 girls and was caught almost immediately with the full roster of the BRExtras save, so I trimmed the number of students down after the full class attempt and barely managed not to have a girl get angry on the reduced class attempt.
With every girl you add, the stream of students coming in and out of the locker room will get bigger and bigger until there is no end to it. This would mean you WILL get caught in a place you aren't supposed to be in and will be lucky to get out without a girl getting angry before you can make your escape. Remember, they only get angry if they reach the point where they run out the door instead of just standing there.
All this said, for those not looking for a challenge to go with their H games, I suggest keeping your classes under the standard 38 limit and/or using the Become Trap mod so they can't get angry at you for going in there.
There is also a box to make them not notice you in Cheat Tools, but the one time I tried it, they still noticed, so it either got unticked or it isn't working.