The textures that come with RAEVWD are for vanilla textures. The QTP3 optional textures are for those running QTP3. If you don't run QTP3, then don't get those textures.
I'm not sure I understand when you say "low res meshes". Did you mean "low res textures"? Meshes don't use a resolution per se as a component. The meshes are optimized to reduce triangles compared to just using the vanilla meshes.
But, when RAEVWD says "low res", they are talking about textures. The textures are low res (256x256) versions of the textures you would find in the "normal" game. The textures supplied with the mod are low res versions of the vanilla textures, which look different than QTP3 textures. So the authors decided to make low res versions of the QTP3 textures for those who run that popular texture pack.