1. Like spycake said, weekday gates usually open 90 minutes prior to first pitch. I'm not sure if the holiday changes that. 2. Short answer, no. Long answer...There are metal detectors and security screening at every gate. Your best chance, as someone else said, would be a baby bottle. There are size restrictions on milk and juice containers for kids and I've seen them sniff check a juice container once. The dad wasn't exactly doing a good job of being inconspicuous about it and the container was 2/3 full. 3. If you're going with the red, white and blue motif, may as well go patriotic on Memorial day and go with stripes! Enjoy the game!