I went to AG's in late April to the Princess Breakfast with my mom and 2 year old DS. We had a really good time. DS was a little scared of the princesses, but he warmed up to them.
We sat down at a table outside by the water (which I had requested) and were given some fruit and pastries. The fruit was very good, but I don't eat grains, so I didn't have the pastries. My mom and DS seemed to like them ok though. A chef came out to talk to me since, like I said I don't eat grains, and he prepared me the eggs, bacon, sausage breakfast without their oil blend (soybean and corn oil blend...ick). Our waiter also took my mom's order and the kiddo's. Mom ordered a similar breakfast to mine and the kiddo ordered the chocolate chip cruiser waffle.
My breakfast was delicious and mom enjoyed hers. The kiddo was not interested. He's a really picky eater and did not like that his boat shaped waffle was on a lake of blue icing. He ate his bacon and some bread and pastries and that was all.
As far as the interactions, the princesses were very sweet with the kiddo. He's a little shy but they fawned over him and chatted with him. It was adorable. I would add pictures, but unfortunately he has entered a "no pictures!" stage. *sigh*
For the record, OP, I don't believe that Ariel's does a princess dinner. I believe it's just breakfast and dinner is World of Color dining.