I am all for using the F slur in a reclaimed sense, but if you continue working on this and eventually release more complete or updated versions consider not using the F slur in any rules text. Especially not flavor text that refers to a player character.
It is still a slur, and even if we reclaim it we need to be careful with it because some people will have traumas and issues related to it. As much as some people may react to being called a slur by reclaiming it others might prefer to distance themselves from it. And even if you reclaim it, it is important to respect others who distance themselves from it. The F slur is sometimes related to feminization kink, but is not inherent to that kink so I don't think it needs to be present and it would be more respectful to omit it in this context.
A player might come along who for whatever reason isn't okay with being referred to by the F slur, even indirectly, but otherwise enjoys feminization kink. It kind of sucks that with the rules text as it is now, that player is excluded by default even if they otherwise enjoy all of the rest of the content in the book. The book touches on a lot of taboo kinks so you might make an argument that the F slur is just another part of that taboo and if someone isn't comfortable this isn't for them, but I just don't think the F slur is necessary in the first place and that using it thus excludes people for no real reason.
The use or prohibition of slurs in play should be part of the safety negotiation at the table. It should not, I don't think, be baked into the rules text and thus assumed permissible by default unless a given TRPG is fundamentally based around a slur. They need to be handled a bit more carefully than that.
Love the concept otherwise, apologies for the long comment I just wanted to be thorough.