I know you asked for Wonka, but I wouldn't mention anything about the two of you or your differences. Just be brief (1-2 sentences) and say just what you said - that you are thinking of her and her family on this day and that you miss her dad and is grateful for everything he did for you. I would not ask her to do anything there on your behalf.

What did the letter from the L say?

M 16 yrs, WH62, P54
3 adult blended kids
EA 11/13, BD1 6/14
PA fall 14, BD2 2/15
Piecing 2015, BD3 12/15
Separated 4/16
WH moved OW in 5/16
Divorced 6/15/17