I am surprised the drilling option is not being pursued, unless the cave surveys are too unreliable to give a target. A dozer and ripper could create equipment pads for drilling quite rapidly, logging teams could take down trees for a clear flight path in and out and the show could get on the road.(A dozer and 360 can achieve amazing feats on slopes even in jungles) I worked for a while on helirigs in Borneo back in the 70's. A chinook or skycrane has way more lift capacity than we ever had, and we were going far deeper than is required for the rescue. A small hole for supplies could be driven in a couple of days.
A 30 or 36 inch cased hole for extraction would take take longer, especially if the ground is extensively fractured. It is also assuming there is no perched water table, that if breached, would possibly compound the existing problems.

I hope the rain holds off and the pumping redoubles. A couple of sumps to traverse instead of long underwater sections would reduce the risks dramatically for an extraction the same route they entered.