They finally added the Golem sounds in the Minecraft Legends wiki and maybe you could use those sounds for your mod. Scroll down to sound between quotes and history for each mob and show the sound tab.
Cobblestone Golem: https://minecraft.wiki/w/Minecraft_Legends:Cobblestone_Golem
Plank Golem: https://minecraft.wiki/w/Minecraft_Legends:Plank_Golem
Moss Golem: https://minecraft.wiki/w/Minecraft_Legends:Mossy_Golem
Grindstone Golem: https://minecraft.wiki/w/Minecraft_Legends:Grindstone_Golem
First of Stone: https://minecraft.wiki/w/Minecraft_Legends:First_of_Stone
First of Oak: https://minecraft.wiki/w/Minecraft_Legends:First_of_Oak
First of Diorite: https://minecraft.wiki/w/Minecraft_Legends:First_of_Diorite
First of Brick: https://minecraft.wiki/w/Minecraft_Legends:First_of_Brick