Is it true that movement through a hedgehog hex is 1 MP, but through beach is 1 1/2 MP's? This is true even if the hedgehog is shown on a beach?
A hex in CC will be one terrain type only. When multiple art is depicted in a hex, the terrain type closer to the top of the Terrain Type hierarchy will be the terrain type of that hex.
Hedgehog is higher than Beach so any hex that depicts Hedgehog and Beach will be ONLY Hedgehog for movement, cover, and LOS.
So, yes, the movement cost through a hedgehog hex is 1 MP.