MATERIALS
All materials have backface culling. If possible, enable it.

tattleFur:
Tattletail uses shell texturing to create its fur. Basically, the mesh is duplicated multiple times with offsets to its vertices and parameters to create the illusion of fur.
Tattletail uses a scale of 0-1 to represent the layer of fur (current layer / total layers), so I'll be using layer% to represent that.

Here are the parameters for Mama Tattletail:
layers: 20
length: 0.02
cutoff: -0.1
shadow (bodyTop): 0.62
shadow (bodyBottom): 0.28
color: #A16853
color texture: Walls2_Albedo.png
alpha texture: Noise.png

Here are formulas for the fur:
color = color * (layer% ^ shadow)
alpha = alpha >= lerp(cutoff, 1, layer%)
vertex position = position + (normal * layer% * length)

This should result in fur which is nearly identical to the game.

tattletailHair: Alpha cutoff is set to 0.045. If the alpha texture is less than this value, the alpha will be 0. If the alpha texture is greater than or equal to this value, the alpha will be 1.
ttFleshTexture: Color is #D7BE9CFF. Multiply with ttFleshTexture.png to get the correct material.