I used what I had on hand to make this drink. Grass-fed butter would offer more health benefits than the regular butter I used. I've never used MCT oil or virgin coconut oil, but either could probably be substituted for the refined coconut oil I used (I cannot vouch for the amounts or flavors, though).
(I changed the name to "Velvety Chai" 12.6.16, but the recipe has not changed.)