You've said any thoughts would be appreciated so here goes. I'm no expert in science and nutrition but have thought about your questions before from the standpoint of a cook.
For the 5 vegetables each day, I'd try to get one from each of the following categories:
1) Something in the cabbage family. That could be broccoli, cabbage, kale, collards, cauliflower, etc.
2) Something dark orange with beta carotene in it like carrots, sweet pototaoes, rutabaga (also in the cabbage family), etc.
3) Dark leafy greens including spinach, kale, arugula, parsley or chard.
4) A squash like butternut, acorn, buttercup (also in category #2), or zucchini.
5) A flavor punch like tomatoes or mushrooms.
I'm buttuming that your question doesn't mean that you intend to eat ONLY vegetables and not get grains, beans, eggs, dairy, etc. If that were the case, I'd suggest more in the way of something with calories. That leads to my thoughts on your second question. If you're getting plenty of other foods besides the 5 vegetables, it is unlikely that you'd get so much of any one of them that you'd be at risk for an end. You'd be getting calories from other sources. If you were trying to limit your total foods to the vegetables on the list and not eat anything else, then a vitamin end wouldn't be the worst of your worries, but I suppose it could happen.
--Lia
chris