I like citrus this time of year - maybe some sort of lemon chicken or fish dish? My aunt recently raved about NYT Cooking's "Baked Fish with Olives and Ginger" recipe (I'm paywalled and can't link, but the header image shows lemons!). You could also do a lemon or grapefruit pound cake for dessert with fresh whipped cream.
I don't know how fancy your party will be, but I really like this recipe, and the individual pies would be fun if you have enough dishes:
https://www.washingtonpost.com/recipes/thai-chicken-potpies/ (I usually use all coconut milk instead of the coconut milk/heavy cream mix).
Roasted beets or roasted squash with burrata or goat cheese and arugula would make a nice starter.