Hi Priti! Yes, you can substitute the vegan milk and butter for dairy counterparts. You won't need the shortening in the frosting if you're using butter, just do all unsalted butter instead!

Hi Amber! I am not really sure what you could substitute with! I usually use either dairy-free yogurt or vegan sour cream. You can try to blend up some silken tofu until smooth and use that instead! I have seen some people use applesauce instead as well but I figure that may be difficult to find in Taiwan as well. I think the tofu will be your best bet!