something i have to say about this festival as you said,
and i think is important is showing different culturals want to see each other and also speak and decide togather to live beter!
in my first logo you can see a yellow old Flower i Find that in old Achaemenid Persian Empire Buildings,
in first see you can see a flower ,that shows friendship,
but in second look you can see many yellow shapes, come to one side! and its your festival,
and also it can tell all people with all cultures is one!
in the second logo as you can see I showed the people and culture with color, and they make a flower together!
and this logo have Iraninan Shapes ability too,that You can see in Iranian Mosque! (Esfahan- Naghshe Jahan)
but thats my idea ,