I'll try to bump your question since I know the frustration of it being buried without any help, TWentz3. I once had my Perfect Resize plugin disappear, and it was because it was not compatible with the latest CC update to Photoshop. I had to wait for OnOne software to create an update in order to make it compatible, and then it reappeared in the proper menu. So check to see if there is an update for Topaz and Nik.
The adjustment layer thing is quite odd. I've never heard of that happening. Hope someone can help with that. When you say 'All of a sudden' do you mean that yesterday it worked, and today it doesn't?? Is it broken no matter how you access the adjustment layer (either by the top menu - Layer > New Adjustment Layer, or by clicking the little b/w circle icon at the bottom of the layers panel) - so both ways results in the same blank layer being added?