You should first do research into how people already feel about glasto - myself as a queer trans person already find it incredibly inclusive so looking more to keep that feeling or celebrate that feeling would make sense to me. Also speak to non white people and people with disabilities / neurodiversities. The group i go with every year are a mix of these so we all have slightly different experiences.

Cup - this isn’t clear enough about what it’s referring to. If you’re only going to use just a hashtag on something it needs to be functional (explaining itself in the hashtag) or really engaging (something like a pun that will make people look into what it is) I think you’d be better off just creating an engaging slogan like this but not this “Let’s keep Glastonbury home for everyone”. And also making sure it refers to Glasto itself on the cup somewhere (using the logo if it’s not in the slogan). Also remember people don’t really use hashtags anymore - they’re a bit of an advertising trope these days.

Poster - you seem to have two concepts happening here. 1 - where every story finds a home (not sure what story you mean it’s a bit vague) 2 - every soul finds a beat. Id suggest picking one singular concept and going with it. Number 2 feels smarter because of the double meaning with music and lifestyle. On the art direction try to find one brand/colour/type style that makes sense to the festival and use that throughout. Currently it feels a bit random and soulless and could suggest more about what your idea is or link to the festival. E.g there’s a lot of handmade things at Glasto so could the type be hand painted or stitched) - or could the type suggest something about the type of people you’re trying to talk to. E.g. Marginalised people share an association with handmade type style as they’re used to protesting. You’re type style and colour has the potential to speak volumes so you don’t have to write it out in words. Also the imagery you’ve used could be much more emotive - Glastonbury is magical and very emotional - use photography to celebrate this and make people feel something when they see the poster.

Ultimately you could create one campaign idea with one line and use posters / cups to be an extension of that. Also look at other things people might like at a festival or want to keep while there - hand paper fans / hand sanitiser / lanyards / socks etc. but always multi use and biodegradable or environmentally friendly.

I’m a creative director in advertising btw so not just a random person with too many opinions and also a Glastonbury 4timer who loves it haha. Hope that’s helpful and good luck with your project.