You can eat at the picnic area near the park entrance.
Yes you can bring food
From: https://www.alcatrazcruises.com/plan-your-trip/helpful-tips/ "Picnicking and consuming food on Alcatraz Island is allowed at the dock area from the picnic tables to the restrooms only."
Yes you can bring small food items. We did so as a family.
No
Yes, you can small items and can only eat them at designated areas.
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