I make my muesli with whole milk yogurt, thinned out with a bit of tea. I usually use lemon ginger tea, but I imagine you could do a great Indian spiced tea with a chai blend. Here's my recipe: http://www.food52.com/recipes/7887_muesli

I would mix the spices into whatever wet ingredient you are using. I'd add the sweetener into this mixure. If it is a milk or milk substitue, bring it up to a simmer and cool it down (if you want cool muesli) before stirring in the oats.