Did the bride give you any specifics? I imagine you are doing tiers, I’d make one vanilla with vanilla buttercream, many people have allergies to chocolate, nuts, etc. and I think everyone will enjoy that. I’d make sure it’s alright with the bride or see if she has any preferences. If not and you really want to showcase your work make each tier a different flavor combo. I think summertime I think fresh fruit! Spongecake will go well with anything, it’s very versatile. Perhaps a white or dark chocolate fudge filling with fresh strawberries or raspberries, very popular flavors of mine.
Petite F are a pain! But mini cakes are a lot of work too! Cookies with the bride and grooms initials are really popular wedding favors, you can stick them in cellophane and tie with ribbon. Just throwing some ideas out there for you :) There is a nice tutorial on CakeJournal.com for PF