Here are some suggestions. I assume the name of the University is on the 'letter-head'.
The university is pleased to invite you to a presentation on its "System of Cool Students" and to the opening of the 'Cool' classrooms: if people don't know anything at all about this
Nona just meant that the word is 'cocktails' rather than 'cocktail'.
On an invitation, 'cocktails' means that alcoholic drinks will be available, often with small snacks as well. People stand around and talk, and meet each other, and drink a little.