https://www.ukclimbing.com/news/item/71031/from_everest_to_the_bob_graham_-_kilian_jornets_plans_for_2017Interesting ambitions.
Bigup to UKB's v own wintermute for smashing AW with a win of 1:32:52. Not far off course record and 5 minutes quicker than 2nd place
Any advice regarding preventative footcare, what to wear etc. There is a drop bag where she can leave dry shoes / socks etc, but it's quite a way after the crossing.
Probably depends on lots of things - how prone she is to getting blisters, how far it is to the drop bag, how long the race is full stop, how competitive she's being etc etc - but if it's a big worry why not just take socks off, cross barefoot (either in your running shoes or without) and put them back on on the other side? She'll probably end up with slightly damp feet but probably no worse than they would be with sweat and stuff and almost certainly better than trying something new on race day (which can be disastrous if it doesn't work out).