Vegetarian here!
During our last visit these were the restaurants I loved the most.. Some might be a little surprising!
Boma - great selection for vegetarians! If you can ask for one the of chefs to show you around the buffet and point out what you can and cannot eat. Love this buffet, it has never let me down.
'Ohana - Yep! The huge meaty meal restaurant is actually very vegetarian friendly. I had a huge and tasty dinner. Whoever was cooking the tofu that night (not Chef TJ - it was his day off) knew what he/she was doing! Great dish with lots of flavor.
Liberty Tree Tavern - Awesome lunch. I have always loved this restaurant, but was a little hesitant to come back after they took the characters away, but decided to try it for lunch and was very pleasantly surprised.
Biergarten - I had an amazing experience here. One of the chefs (I feel horrible, because I cannot remember his name for the life of me) walked me around the buffet and pointed out what I could eat. He made sure to mention if something was cooked with chicken/beef/fish stock. And made me a wonderful mushroom sauce with crispy fried onions to go with the spatzel since their normal sauce on the buffet isn't vegetarian. He also made me some stewed tomatoes that tasted just like my mom's! It was such a lovely and wonderful gesture and I appreciated his extra kindness.
I will also mention that we went back to 'Ohana for breakfast and it was wonderful. We just had the meat served on a different plate and made sure the potatoes were 100% vegetarian. I cannot express how much I loved this breakfast and I am REALLY not a breakfast person.
As for CS meals.. These were the ones I really liked..
Flame Tree BBQ - Great fruit plate. It is also served with honey yogurt, but I was unsure if there was rennet in it - so my son ate it for me. It was really very refreshing and definitely large enough for me to share.
Sunshine Seasons - First meal I tried here during our trip was the tofu noodle bowl. AWESOME! Loved it! Very, very tasty and I was incredibly happy with it. Again, someone knew how to cook the tofu. Very crunchy and flavorful. I'm super picky about tofu. Either it needs to be super crispy and light or serve it to me hiyayakko style (minus the bonito flakes) with fresh ginger. Anyway! We went back to Sunshine Seasons later in the trip and I tried the grilled vegetable sandwich and just didn't really care for it at all..
I hope this helps and feel free to ask me anything you want.

Have a great trip!