You only need a little. Fat disperses flavor.

Butter corn miso ramen is a thing in Sapporo. Probably invented to promote regional products (Hokkaido is famous for corn and dairy) to tourists.

Yes. Not a whole bunch but it makes it like a creamy texture. Idk I been eating it that way since I was a kid. The mustard normally trips people out too, but when they try it they say its good.