Dress attire for the wedding is beach casual. Here's some inspiration: https://www.theknot.com/content/what-to-wear-to-a-beach-wedding
Yes. We hear Ubers are an easy option. However, a friend who traveled to San Pancho this year said that Ubers don't pick up at the airport. So when you arrive, if you'd like to take an Uber, walk over the pedestrian bridge toward the restaurants and use that as your pick-up spot. If you'd prefer to arrange for a car service, check out https://sanpancholife.com/business/discovervallarta.htm