You are correct on the wine, most everyone has a at least a decent wine list. I'm not sure about vegetarian meals, but seafood and steak aren't a problem.
My personal Top Seafood and Steak places as follows, these two aren't in Paso, but nearby. If you're going to have wheels anyway it's fun to get out and about.
Seafood: 30ish minute drive to Cambria, go to the Sea Chest Oyster bar and restaurant. On the beach, it's been there 30 or 35 years and I think the same couple has owned it the whole time. Bring cash as they don't take credit cards. Or reservations. Just AWESOME food. If you don't want to wait for a table you can sit at the oyster bar and watch the chef's do their thing, lots of fun. I had the coippino last time and it was incredible, I ordered the large pot and couldn't finish it.
Steaks: Head down 101 about 15 minutes to Templeton for AJ Spurs saloon and dining hall. Very old west feel, great steaks and large portions. Beans and salsa for an appetizer, large variety of items on the menu. It's been a number of years since I've been there but it's always been great.
Around the square in central Paso there is quite a selection as well. Chico's cafe has a very talented chef and the seafood there is great, haven't tried their steaks. Their calamari appetizer is as good as the Sea Chest, maybe better, nice wine list. I ate there last week and had a great scallop and shrimp dinner.
Within a few minutes walk around the square you'll find a wide variety of places who's names I don't remember, from an Irish pub to some very eclectic choices.
Good luck and have fun!
Doug