Those words from Lilysa sound like she's forcing the ultimate cucking onto Mikarin. Don't give me the vapid "You'll still be you", Okumura getting together with Lilysa would be an unsurmountable strike for Mikarin and she'll obviously drift away from both of them and the club.
There has been so much buildup about her long lasting unconditional love, and too many inner monologues from Okumura finally acknowledging her feelings and understanding her actions...and yet they haven't adressed them properly in a conversation. I still have hopes that he's doing this comiket as his last job to boost Lilysa as a cosplayer, so he can move on to properly face Mikarin and confess his love to her.
Yeah I know, I'm absolute high on hopium, but I just don't see Okumura and Lilysa as a couple. There has been too many ambiguous words and situations that make me doubt his love for her is romantic.
I think, it could go either way from here :
1) just like you said, okumura realize his feelings and Mikari wins
2) okumura realize acknowledge his feelings that he indeed loves Mikarin, yet he realize it too late and know fall in love with lilisa. While Mikarin accept that and finally move on.
For me the latter is the most heart breaking, but unfortunately the most likely to happen. To be honest i don't want that to happen at all, but it's not my manga, let see where the author goes about this now. But if this story is indeed the pararell of ashford chronicles, then i hope the girl who love her man with all her heart gets rewarded in the end, and the way i see it, the liliel, the "real" liliel in 2.5 dimensional seduction is not lilisa, but Mikarin.