Gluten-free review:
This place is a must in the summer, despite the long lines. They have a large selection of ice creams, gelato, and sorbet to choose from, many of which are gluten-free. I tend to stick to gelato, most of which don't have gluten. Whenever I've asked they have been very helpful in telling me which ones I couldn't have, but often they're pretty obvious because the chunks of cookies are visible or in the name.
You also have the choice of getting your cold goodies in a new cup with a new spoon, so very little to no cross contamination is there. You can also ask them to use a clean scoop if your allergies are severe, which I don't ask for and have never had a reaction.
TL;DR many gluten-free items; get a cup over cone