I don't recall it saying anywhere that you cant mix fruits and veggies. It says to have fruit and a veggie at lunch, so you should be fine. That sounds good...might be my dinner salad LOL.
The veggies don't matter if you wanted to eat the same ones twice a day. It is the protein that should not be eaten twice in one day, however, I have eaten chicken both times many times, for lack of anything else to choose from those days.