Update: RotaryCraft seems to override ExtraTiC for HSLA steel, and Reika explained that there are no HSLA parts. Since the HSLA 'vanilla' tools were not disabled as part of ITT, you should still be able to use them. I don't know if I can force ExtraTiC HSLA parts without disabling the RoC bedrock parts, but we'll see.
That aside, it'll still be several more hours before I'm back at my desktop to review the issue with Platinum and Fossils mod coal. Also, I discovered that the TiC/NEK issue persists if I reconfigure ExtraTiC, so, until the interaction problem is resolved, I'm just going to remove "Not Enough Keys" from the modpack for the time being. So, if you don't want to wait for me, you can go ahead and disable it if you're having problems with the TiC armor GUI forcing itself up after closing.