I'm a once a year guy. I suspect we will purchase a few live shrimp and frozen squid. Obviously I'd like to catch trout and redfish, but if we can convince a few fish of basically any species to bite, the boys will be happy. Please share your knowledge now.
Which jetties on Mustang? There's a jetty on both the north and south end as well the middle of Mustang Island. For reds/trout live shrimp is better than squid especially if fishing the jetties.
Most basic fishing is probably the piers at night w/squid or cutbait for Gaffies/other fish or fishing surf with fresh dead shrimp or Fishbites for Whiting & other species, if the surf is not too rough.
Trout/reds are gonna take a bit more preparation/specialization for constitant catches, but lots of it depends on the water conditions and locations you fish.
Suggest you do a search on here looking for posts answering or commenting on your questions. Key words like trout, redfish, port Aransas, jetties should give you some results and after reading up, come up with a game plan of possible action, post it and let folks suggest changes/fine tune or agree with your plan. That'll be the best way to get some serious input.