They are good at accommodating most things. In the buffets Cabanas there are many types of milk including soy.
Inform them in advance, and speak to your head server onboard.
IE I do not eat seafood or fish it was noted, and also they would advise on each meal. I recall ordering chicken fajitas and didn't notice there's came with anchovies. They told me.
The buffets apart from milk occasionally us an issue if labels get move around, best to ask.
In the galley tour they show you seperate areas for preparation.