Looks like you covered everything. Sorry I wasn't a help. I'm not sure what could break two specific companions and no others, that's very odd. If it was happening to me, only thing I could think of to try next would be replacing, or removing, all their gear. I can't imagine why any piece of gear would break that behavior, but you never know for certain how code's going to interact in a large program until it happens.
After that, I'd be flailing around in the dark: talk to them at Skyhold and advance the convos, bring them out in different combinations of other party members. Anything that affects them that might "unstick" them.
Well thanks for trying anyway. It seems I have managed to break Solas too now, he doesn't want to heal now either lol. I think it may have happened after I changed his pots to all, not too sure. I've tried advancing in quests, changing their gear and even reinstalling the game but nothing seems to work. So meh. This is like my 10th playthrough but my first on nightmare so the pots thing is kind of yeah...
