Question about Nylea and mutate

Hello, I'm working on a Kotis mutate deck and am looking at including [[Nylea, God of the Hunt]] which cares about devotion to green.

I'm including as it gives trample and a pump on an indestructible card.

I am needing help to determine when Nylea would be a creature if all I have on the battlefield is Kotis mutated with [[Migratory Greathorn]] and [[Sawtusk Demolisher]] and Nylea.

Does Kotis just have the pips of the top mutated card or all of the cards total? Also, Nylea see the creature cost different from the alternate creature cost (mutate)?

Thanks in advance!