No worries, I'm happy to help as much as I can.

I'm just looking into this now and you're right, I don't see anything that is out of place with the naming conventions or in code, so I think you've got that all correct. Unfortunately that means this might be a trickier problem to solve, but I do have a couple of ideas that you could try to help troubleshoot.

First and foremost one thing you can do is use a tool like 7-zip to open up your mod's .jar file after you've built it, and make sure that the texture is actually showing up where it should be (I think inside the jar it should be in /assets/cosmicCraft/textures/blocks/) if it isn't there or if the file path is wrong in someway inside the jar that could be part of the issue and would suggest something is going wrong in the build itself.

Another thought is that you might be having trouble because there is a capitalized letter in your mod's modid, normally those should be lowercase (and in later versions of Minecraft it is actually required to be) so you could try changing the modid from 'cosmicCraft' to 'cosmiccraft', although I admit I'm less sure if that is the cause of the problem and it would mean renaming other instances of 'cosmicCraft'else to the lowercase format as well.

I'll try to come up with some other ideas about this when I have a bit more time tomorrow too.