well if you're playing in dream mode its probably not working due a choice made earlier in the game and not your stats(im only unsure about the lust stat but again this can be adjusted whit a earlier choice)
so i might be because off that
I know that for lily allowing mina to be whit her is a big choice
but i also know from my realistic playtrough that if you choose to keep lilith more prudish or don't want her to influence her you miss big lust points
( if you allow mina to be whit lily and keep stacking Lust points(always pick sexual choice) getting lily would be easy as far as i know)
Maybe
KKpotato can enlighten us on which specific triggers are needed(pretty sure its allow mina to continue and high lust)