Texture paths:
You need to change the path of the texture inside the dae file.
Example:
Before: http://puu.sh/jmUbX.png
After: http://puu.sh/jmU68.png
Wrong texture formats:
Only PNG is accepted. Formats such as BMP, TGA, DDS, etc. are not.
DAE exporter issues:
Different exporters handle things differently from others.
It's the exact same case with different importers.
Not much you can do aside from using a different exporter (but even then some importers don't like files exported by certain exporters, it's a huge hit or miss situation)
The file imported without issues for me, after I fixed the texture paths.
Spec masks:
Can't see any issues with them, as they look like regular specular power maps.
Maybe they were talking about the fact that you left one in as DDS?
Alpha channel:
If the alpha channel in the diffuse color texture is used as the opacity map, then you should leave it be.
In all other cases, seperate it as it's either not used for opacity but used to store another kind of texture (eg specular power level, shader mask (decals such as blood for example)
Side note:
You're also required to submit an OBJ of the model, so export an obj of the model and it to the submission sheet.
Don't forget to fix the texture paths in the .mtl file similarly to fixing them in the DAE file.
As far as FBX goes, you don't have much control over how things in the fbx are exported, so if it's works for you it should be accepted.
I personally prefer to export FBX files in the 2006 version, as that's the oldest- and thus the most compatible version.
You need to change the path of the texture inside the dae file.
Example:
Before: http://puu.sh/jmUbX.png
After: http://puu.sh/jmU68.png
Wrong texture formats:
Only PNG is accepted. Formats such as BMP, TGA, DDS, etc. are not.
DAE exporter issues:
Different exporters handle things differently from others.
It's the exact same case with different importers.
Not much you can do aside from using a different exporter (but even then some importers don't like files exported by certain exporters, it's a huge hit or miss situation)
The file imported without issues for me, after I fixed the texture paths.
Spec masks:
Can't see any issues with them, as they look like regular specular power maps.
Maybe they were talking about the fact that you left one in as DDS?
Alpha channel:
If the alpha channel in the diffuse color texture is used as the opacity map, then you should leave it be.
In all other cases, seperate it as it's either not used for opacity but used to store another kind of texture (eg specular power level, shader mask (decals such as blood for example)
Side note:
You're also required to submit an OBJ of the model, so export an obj of the model and it to the submission sheet.
Don't forget to fix the texture paths in the .mtl file similarly to fixing them in the DAE file.
As far as FBX goes, you don't have much control over how things in the fbx are exported, so if it's works for you it should be accepted.
I personally prefer to export FBX files in the 2006 version, as that's the oldest- and thus the most compatible version.