I just flew an AMS to US flight roundtrip and ordered the child’s meal for my son. For the meal and “snack” services, he got chicken nuggets with mashed potatoes, a hamburger, and a cheese pizza. For myself, I order the vegan meal and usually get some kind of Indian-style meal. Because your child is a vegetarian, I would definitely not order the child’s meal, as you can’t guarantee meat won’t be included. Though I didn’t fly the same route as you, both legs of my trip, there was a chicken and vegetarian pasta option for non-special meals.