I will only say it this time... but I hope Lily will grow out of this "crush".
It is "cute" to a certain extent, but Lily being a succubus and having an aggressive secondary personality, and she herself being quite possessive too, and well... her being a child.
Makes this whole part icky, luckily... Hajime clearly treats Lily as a daughter.
But considering how much these last few arcs have focused on Lily's possessiveness with Hajime, and it clearly isn't the father/daughter jealousy, I hope the author will leave it behind.