The breakfasts at the cafes we ate at were extensively garnished plates with rolls, cheeses, sometimes meat or else scrambled eggs (occasionally fried eggs). I like cafe au lait here, so I really enjoyed German Milchkaffee. My husband usually drinks his coffee with about half the cup full of half and half, but people in restaurants had no idea what he was talking about when he'd ask for cream in his coffee, and we never did find anything very equivalent in the grocery store, so he settled for Milchcaffee when we were out, and whole milk at the AirBnB.
We were never brought water without asking, and we didn't ask. I think my son did ask for "Leitungswasser" (tap water) once, but decided it was not worth the bother. I think one place he did get Coke with ice, but otherwise not.
The second night we were in Kitzingen, I had to laugh, because my son and I both had fries with our dinner. They brought him a packet of ketchup, but not me (making a judgement that he would want things more American-style). Usually ketchup was in a small dish (along with a small dish of mayonnaise, because that's what Europeans like), and not as much ketchup as we were used to.
It seems that German law requires menus to list allergens and additives for each dish, so that would be very helpful if you had concerns or sensitivities. Berlin is a restaurant paradise for vegetarians and vegans - every place had quite a selection. Even in Kitzingen there was something vegetarian or vegan on every menu.