So uhm oh we all gonna ignore that Jasmine doesnt even show up at lantern's?
I did, until just now when you pointed it out
Well let's talk about it:
Gameplay wise there is no real reason for her to ever show up there, since she doesn't progress as the other girls do.
You could get a "Good Husband Point" once the two of you are married but that's about it, when it comes to mechanics.
But still that's something if you are married to Jasmin and Jasmin alone you are missing out on one potential yearly "Good Husband Point" - plus the ones for the "Wardrobe Malfunctioning Circus", "the Strongman Contest", and "the Gardening Competition" - 6 in total.
Character wise it wouldn't make much sense for her to attend the festival with her advisor, but it would if she was going with her husband. Yeah, the marriage gets of on a rocky start, but even her just being there to use her wish to insult the Old Man, or bitch about something, would be perfectly in line with her character and a nice touch post game wise. (You can take her to the movies after all which also only ever provide "Good Husband Points").
Yeah I think it would be a nice touch if she went. Even nicer if you could take her to the other unavailable events - or invite her at least. I can totally see her character shooting down your invitation to the "Strongman Contest"/"Gardening Competition" cause something something peasants - but the Circus should be right up her alley at least as much as the movies.
So I wanted to see if she addresses the fact she doesn't want to go to the Festival. Loaded a save in which I had married her, skipped to the festival, went to see her on the Harem Floor - only to find out the Harem Floor is inaccesible during the Festival. Reloaded, tried again, this time making sure to appoint her as my Main Wife and went to see her.
Result: She's moping (as she usually does), but no Festival specific dialogue, might be random, in my case it was *Hmph!*