you can have max 8 textures for 1 material.
you could also add 2 materials in blender or more (i think so): (if you have 2 or more objects in your scene with UV maps you assign each of the objects a material and then you could have 2 texture sets, each for one object)
for example:
Object_01 (own UV Map)
Material_01_Name
<Material_01_Name>_BC.png
<Material_01_Name>_RN.png
<Material_01_Name>_CA.png
<Material_01_Name>_AO.png
<Material_01_Name>_MT.png
<Material_01_Name>_OP.png
<Material_01_Name>_EM.png
<Material_01_Name>_F1.png
<Material_01_Name>_F2.png
<Material_01_Name>_F3.png
<Material_01_Name>_F4.png
Object_02 (own UV Map)
Material_02_Name
<Material_02_Name>_BC.png
<Material_02_Name>_RN.png
<Material_02_Name>_CA.png
<Material_02_Name>_AO.png
<Material_02_Name>_MT.png
<Material_02_Name>_OP.png
<Material_02_Name>_EM.png
<Material_02_Name>_F1.png
<Material_02_Name>_F2.png
<Material_02_Name>_F3.png
<Material_02_Name>_F4.png