It is my understanding that Tandoor chicken, while grilled, has been marinated in yogurt. So not ideal. You could see if they have Kadai Chicken which is spiced, but not marinated in yogurt. I have generally found that indian restaurants are not easy but the people are easy going and can try to make it work. It's a challenge though. Any chance you can swing by their restaurant and check out the menu?
Ok I make indian/Pakistani food every day. Stay away from Masalas, curries, kharis, pilau and biryani. They contain rice, fried onions, yogurt and tomatoes.
You safest bet is chicken tikka- simple dry spice rub and grilled. you can eat goat or lamb kabobs. You can do lamb kebabs- but ask is they have onions in them but do not eat shami kabobs!
And of course avoid- naans, roti, rhita (yogurt with chilies, onions, cucumbers ect)
My favorite Indian food dish is Palak Paneer, because it is mostly spinach..but they do put cheese in it, so this could be a problem. You may be able to ask for it without the cheese though, although it may not taste as good.
Paneer means cheese. It is super easy to make, I love paneer with just about anything in it. YUMMYYY!! But not IP friendly
Just like the word Chi mean tea in 30+ languages, so I laugh when someone says they are having a Chi Tea Latte