please suggest a few gluten free dairy free (sprinkling cheese on top ok) vegetable dishes to accompany rack of veal with orange and herbs

You're asking for gluten & dairy free.
Some people who avoid gluten can tolerate rice.
If not, make cauliflower rice (many recipes out there, chop in blender or processor or some stores sell ready-made).
I also (like MMH) love to serve multicolored roasted root vegetables (carrots come in purple & yellow, as well as orange; there's a broccoli-cauliflower hybrid in light green, plus regular ones in their normal colors).
To get some green on the table, mixed dark green lettuce salad, maybe with roasted nuts as garnish. Play on the orange in the main dish by using it or another citrus juice in the dressing.

Veggies are gluten free. If you are interested in low carb, avoid root veggies. Roasting almost any veggie in olive oil, garlic, salt & pepper at high heat (400) is wonderful & brings out their sweetness. Just watch closely because cooking time can vary depending on the water content. They are fine served at room temp so they can be done in advance. Our favorites are - Brussels sprouts (roast with bacon or pancetta), cauliflower sliced in "steaks" (roast with springs of fresh thyme), multicolored carrots sliced in half length wise are beautiful as well (roast with sprigs of fresh thyme), baby potatoes sliced in half (roast with fresh rosemary), quartered red onion, broccoli heads sliced lengthwise, beets (wrap in foil & sprinkle with red wine vinegar & they wont bleed on your fingers). Zucchini sliced in ribbons is also great but cooks much faster. Use both colors for variety. I do this early on Thanksgiving day & serve room temp (not the potatoes). Enjoy.

Grilled radicchio, brushed with oil or wrapped in pancetta goes well with veal.
Polenta is gluten free and also makes an excellent accompaniment.

Roasted Brussels sprouts. Toss in good olive oil, maple syrup or balsamic vinegar, and salt before roasting.