I had a few of these appear on my 4s. No reset ever got rid of them. They seemed to coincide with App Store updates not completely downloading. I'd get the completion circle but the app wouldn't update and I'd be left with the blank icon. After a restart the app to be updated would be gone from my home screen and I'd have to re-download from the store. The updated app would then appear, but the blank icon remained. I submitted it as a bug.
I have seen this before on my iPhone 6 (iOS 9.something) when I disabled News. I think one of the greyed-out icons could relate to the News app if either you disable it, or it's not available in your region. But that's just a guess.