Padre Island National Seashore with Eric Ozlins, Ocean Epics Charters. You can go out for a day or overnight trip, I highly recommend the overnight, catch sharks, etc... You can read his articles to get a feel for the trip on Texas Saltwater Fishing magazine.
You can also fish for all three of those species with guides that specialize in that trip Aug-Oct, called the "ironman" trip by Mike Williams out of Galveston, but there are a number of guides that do these trips out of there, Port O'Connor (Patriot, Bill Cannan?, etc...), and probably other places.
Best of luck to you, that sounds like a great trip for your family!
Many men go fishing all of their lives without knowing that it is not fish they are after. Henry David Thoreau