I'll start with I play on PC and I don't use any mods. I started a new character for the event, a single female living in Willow Creek. I was able to do the event through the planting of the flowers ...
Ideas
I had the dissapearing newsletter and tried everything, just now i went into a household and had the child get the mail and try to read it, IT WORKED! idk if it will progress more but it shows progression on all my households now. excited.
I just did this and was able to progress, thank you for the tip!