I will not be surprised if we learn ED is alive and with the hiker who gave her a lift on November 19th.
Hi Puzzles. I sure hope you are right! The lack of communication for 2 months with family and friends, from someone so caring as ED, is odd and may not fit well with your theory. That said, we know LE connected with the 19/11 hiker who gave ED a ride back to her van, but we don't know what LE learned from their interactions and time together - and if they communicated afterwards. To know more about ED's state of mind three days before her final contact with DC would be invaluable.
For ED to voluntarily disappear with the hiker (or someone else) and leave her life behind would take some planning of course. And perhaps that is what ED did during 20/11 - she had made her decision and needed to get a plan together. If we continue that thinking, perhaps the plan was to meet up with someone on 22/11 at the Refuge de Vanesque. Since there is no cell service there, perhaps ED planned to summit Pic de Sauvegarde to see her friend arrive at the refuge on 22/11 (and they to see her).
So on 21/11 - taking this theory further - ED might have hiked up the col as reconnaissance so she would know how long it would take, to minimize anxieties about the new trail, check cell service, etc. That could be why she simply descended 21/11 afternoon to stay at Cabana de la Besurta for the night (or more likely, back at her van in Banasque since she hadn't planned to summit again until late the following day). In this scenario, my guess is ED went back to her van. And if this scenario is at all real, then on 22/11 ED could have told DC she stayed at the Cabana since that would be more in line with her stated hiking plans (and her van was ~ 9 miles away).
Then on 22/11 - taking this theory further - ED hikes up to the summit from her van. When she encountered the skier at ~3pm she was hungry or thirsty from hiking several hours and was hoping for something fresh to eat. That kind of makes more sense if she was hiking from her van that day and not from the Cabana at the trail head. And as RickshawFan has opined, ED could have left her "heavy pack" (was it extra heavy that day if it had all her possessions?) at the Port de Vanasque and hiked up to the summit light. Then, at the summit, ED caught up with DC's texts from 21-22/11 (perhaps she was ignoring them), connected with family and communicated with DC.
ED might have planned to do all that communicating on 22/11 before meeting up with someone - in essence saying good-bye. It could also explain the vagueness of information ED conveyed to DC in her texts (e.g. "winter room"). It could explain what I first interpreted as ambivalence to get going if she was waiting for someone. And it could explain ED's joy that DC recounted, if she was making a break from a life that made her unhappy. Then after the final communication (that oddly brief WhatsApp video chat with DC) maybe ED saw the person she was to meet arrive at the Refuge, and she descends through the Port de Vanesque to meet him (or her).
From there, who knows. I suspect they could have continued on towards Hospice de France that evening and bivouaced in the valley. And perhaps that person she was meeting was planning to bring food provisions for them and that may be why ED was looking for fruit at 3pm - she had little food with her. And in this scenario, I think they could have hiked together around the 'loop' the 19/11 hiker told ED about and exited the trail beyond Port de Glere where the hiker may have come from on 22/11.
The third party ED might have been with could have had a car parked at the Hotel Hospital de Banasque and off they went to wherever ED is now... alive hopefully!
OK, this is A LOT of theory - suspended reality if you may! And a bit of wishful thinking. But I thought I'd throw it out as an attempt to fit the data (including no sign of ED) to a voluntary disappearance scenario. However, for this to to be a viable theory, we'd have to accept ED was capable of deceiving DC and her family... can we?