@ffphier confirmed that a dispel from an ice hero no longer works against Mitsuko. V25 says direct mana reduction is a status effect - #68 by ffphier
The damage is REFLECTED, and the dispel is RESISTED.
The one problem with taking her in Grimforest is that red is reflected, and Red will probably be a boss with Snow White.
One remaining uncertainty is if Snow White will dispel the negative effects (let’s say stage 15 is Snow White, Boss Wolf, and Red Hood). If BW fires his mana debuff against Mitsuko, will SW remove it when she fires? She should, since removing a negative effect isn’t a negative effect.
P.S. my apologies if this is all too far off topic and needs to get merged elsewhere.