The ghee's I've had are fairly tasteless...I am not sure if that would be a good thing or bad thing in this case. Otherwise a rich butter would be my suggestion too. Raw sugar crystals (the brown ones) to sweeten and a little Himalayan sea salt seems appropriate.
I am not sure that tasteless is a bad thing there seem to be 2 schools of thought.
A) Which my gf in Malaysia saw on a documentary on Malaysian TV 2 weeks ago - and which I have seen corrobortaed on a number of websites.
The butter is only supposed to act as an insulating film on top of the tea, it keeps the tea hot, blow it to one side before sipping the tea.
B) There is something called a Chandong which is a large wooden tube with a plunger - translated as a 'Tibetan Butter Tea Churn' - the plunger helps the melting butter to be emulsified into the tea. This surely would be in direct contrast to the first practice