In terms of what bag you should bring, I am a huge fan of the duffel bag. It is easy to pack, carry, and not too big. Include a makeup kit, brush, makeup remover, and an extra shirt. I also always freeze in cars so I always wear layers.
The first outfit is a casual outfit you can wear to almost anything. The second outfit is an idea you can make casual or dress up if you need to. A shirt dress is really nice for this. If you choose a silky material or suede then it looks a little more dressed up. You can add a blazer or jacket and it doesn’t seem quite so informal. Also add a pearl necklace and earrings and you’ll be fine!