The idea of an outdoor wedding is lovely. The actuality of an outdoor wedding can be horrible: sweating heat, bugs, rain, hurling rain, more rain, way too windy.... you never know. And I hate wearing any kind of heels outdoors they sink into the grass, so even if you plan on flats, many of your female guests will wear a dress, even a casual sun dress, and some sort of heel which will go right into the lawn.
I would take photos outside and find an indoor place for the reception.
Many churches and VFW's have halls to rent. Skip the whole sit down dinner. In fact have a late afternoon wedding and just do a dessert buffet with a wedding cake. No need for alcohol. People can live without alcohol.
I love the idea of asking family to bring desserts. Honestly, I think when people rsvp many will say, "Can I do anything?" Money is tight everywhere.
I went to school in Wisconsin and it was very common for people to bring food for the dessert table. I went to one wedding where everyone brought a dish to pass.
You can stand around and actually chat with everyone. People can catch up. There is no need for music, unless your friends and family are huge into dancing. If that is the case bring on the music.
As for your dress where whatever makes you feel beautiful. Same with your girls.
Why people spend a fortune on weddings, instead of focusing on the ceremony and a lovely party I will never know.