You're probably going to have to make compromises on your budget. Your budget is not enough for both (1) Living by the beach and (2) not roommates. And that's even before considering the other stuff you care about like being in a safe area and around other young people.

This is /r/orangecounty and the beach cities here are incredibly expensive to live in. Unless you're single, no dependents, and making $150k, you're going to effectively be poor in a place like Newport or Laguna Beaches. The money in those 2 cities is wild.

I think the only beach city you have a shot at affording in Orange County is Huntington Beach. You might consider Long Beach in LA County or something in San Diego county.