I still think you should go with flat bars for her symptoms. Yes, she can ride the tops of drops but her arms are turned inward. With a flat bar, you have a wider bar. I would even think about something like the FSA Metropolis bar that angles the hands out. Another bar is the MAP/Ahearne bar. This helps keep the arms to the outside of the body and helps with better control of the bike. It also helps in keeping the chest open, for easier breathing. Put the Ergon grips on as you have said and she might like it. Full disclosure here, my custom bike has MAP/Ahearne's with Ergons and I have three pair of FSA Metropolis bars in my parts bin because I like them so much.
Wheelsets and supple tires can make a world of difference in how a bike feels on the road. My recommendation, Rene Herse Loup Loup extra lights if going 650b. For the rides you describe, 47 mm is overkill. Tires in the 38-41 mm would be better. Changing to 650 will lower the bottom bracket a few mm but for the riding she is doing it won't matter. You would have to make sure the bike could handle the wider width tires, especially the fork. Carbon wheels to look at are the
Light Bicycle wheelset. They have are inexpensive as carbon rims go but have a great reputation.
Good luck on finding something that works for here. There was some helpful advice already posted and of course some dogs to (which my advice may be also).