You can make tzatziki with it, or salad dressing, making a mango lassi with it would be a different texture. Frozen yoghurt seems like a good idea, I wouldn’t expect it to kill the cultures, generally high temperature kills stuff, low temperatures usually just slow them down and keep populations from growing, so cooking with it seems more likely to kill cultures than freezing it. if it weren’t for what I just said about cooking with it I’d say using it in curry would be great, though you usually add it at the end so you could do that as it’s cooling some and potentially avoid that issue