Newport Beach is an excellent choice!!! I'm not familiar with the transportation options, but I can tell you that parking can be difficult. (In fact, that's the only negative thing you will ever hear me say about Newport!) So if a shuttle is an option, that might work well.
Also, keep in mind that Newport includes both the Newport Pier (busier, more bars) and the Balboa Pier. If you have kids, then the Balboa Pier is a great option - Ruby's restaurant at the end of the pier has a carry out window and inside/outside seating. The Fun Zone is located near the Balboa Pier, and you can take the ferry over to Balboa Island for shops/restaurants on Marine Avenue (turn right when you get off the ferry and walk several blocks along the bay to Marine Ave. and turn left.)
If you are near the Newport Pier (which is at about 20th street), there are great spots on the beach near 15th Street. They have bathrooms, outside showers, 15th St. Surf shop for rentals, Fry's Market for beach toys, sodas, candy, and the Stuft Surfer for burgers, ice cream, soda, etc. Stuft Surfer has limited inside seating, but you can carry out or eat on the picnic tables on the sand. There is also a great playground on the beach in front of the elementary school at 13th Street.
As always, happy to answer any questions about Newport!!! (Except for the shuttle/bus ones -sorry!)