Games is missing textures for some vanilla items as well as some of the super massive tech, solar flux, Dalek and jabba mods. instead of appropriate textures i am receiving Black boxes or just empty air

This seems to be on your end. Please try reinstalling the pack and updating the graphics driver.

I tried reinstalling the pack however no changes were made

Can you post some screenshots of it and tell us which items?

For anyone with a similar issue as this you should try to go to the resource packs tab in the options menu and click done. this fixed the issue for me

that was what i was experiencing however it seems i have fixed the issue

Great that you got it working