I already see the problem. The blending modes that you set in spine DO NOT come over to unity. That's the reason you guys are hitting snags. You can set blending modes in spine just to make sure things look right before exporting and stuff, but ultimately you just have to do it in unity.
step1 - in unity create a skeleton animation in your hierarchy.
step2 - add component 'skeleton renderer custom materials'
step3- make a new material. You can use other shaders, make your own, or just use the ones provided by spine. So for instance lets make a multiply layer. Make the material, select shader/Spine/PMA Multiply. Then, add the texture you exported from spine to the Main_Tex of the material/shader (if youre using multiple texture sheets per image, you just need to make multiples if you needed things from all of em - otherwise just chose the 1 with the thing you need multiplied).
step4- back in the skeleton renderer custom materials... if you need to make ALL of a texture multiplied (like say, you exported all your shadow layers in 1 image, and all the base art on another image) you could simply just override whichever material you need to. if you need to access a specific slot from spine, that's just at the top under custom slot materials. Either way, simply drag your material into the material slot provided.
try it out with other shaders as well and see what kind of effects you can get/what works for you!
