Hmm. I will assume we are talking about a lacto-ovo vegetarian and not a vegan or one of those people who eat fish and poultry and call themselves vegetarians. If you do eat either of those things, you'll be fine. I'll write with an eye toward vegans, just in case.
Like many places, Disney does unfortunately tend to be heavy on the pasta options for vegetarians.
It's not a bunch of choices but the menu there is pretty slim in general, as the kitchen is fairly small.
The portobello gorditas are definitely vegetarian and without the cheese would be vegan.
The grape leaves stuffed with goat cheese should be fine.
I feel like there *might* be pancetta or something on the simple green salad. It has brie and I know it's not really all that simple. But any meat could be left off.
The heirloom tomato salad has a parmesan dressing but I think Mamma Silva got it without. It comes with a lemon olive oil sorbet that "feels" to me like it has egg in it. It shouldn't, because sorbet doesn't, but if you aren't ovo vegetarians, I'd ask. It's awesome, though.
At dinner they have a watermelon salad that comes with lime mascarpone.
The pappardelle pasta comes with chicken meatballs but the sauce seemed like pretty straightforward tomato sauce to me (albeit made from yellow tomatoes). So without the meatballs it would still be a pretty nice plate of pasta. It's the one pasta they make in house. It looked as if it might be egg pasta but I didn't taste it.
There is a daily pasta now, it looks like. So one to ask about. Also a daily soup; they will know what's in the stock.
And there is a kids' pasta that comes with several sauce options, all of which are meatless. You should be able to get that in an adult size and price.
The ice cream, fortunately, is awesome. Don't forget the kids' desserts.
And remember that this is a somewhat seasonal menu. It won't change every week but I wouldn't be expecting tomato or watermelon salad in the Fall...
I've always gotten the seating despite not always ordering an entree. They seem to be looking more for a minimum dollar spent.
We've never gotten around to using out seating, though. I think if you read the "Carthay Circle, Who's Been" thread, you'll find some comments on the seating and what people ate to get the seating.
I've found them very knowledgeable about what's in the food. The chef is right there if there are any questions... Substitutions are not always that easy because many of the stocks and sauces are made in advance. If you are interested in having them make you something special, I think you'd do best to put in a request to the dining line.