Minecraft zipped version file not there

Resource packs will only replace the graphics (and presumably sound effects) of the resources they are overriding. Everything else will, in general, default to their vanilla graphics. I have often used an HD vanilla texture pack in a modded environment. The contrast between what is replaced and what is not is not really that big of a deal unless the texture pack is a drastic change from general minecraft appearance.

I don't know why you were trying to open the .json file. Those files are basically pure text and have nothing to do with the textures. Try to open the .jar file using "Open With" and then selecting 7-Zip or WinRAR (I personally use WinRAR).

Once open, the textures should be under assets –> minecraft –> textures