Here's my first attempt at "re-constructing"
I used some ideas from an Au Bonheur pattern I'd made with pockets and flaps hanging all over it http://www.patron-de-couture.fr/uploaded/1/big/JCE09002.jpg but in this version I decided to use as many of the pockets on the pants themselves as I could. What fun---there was even one with a ribbon closure!
Only one of the pair of pants fit me at the waist so I used that as the "base", taking apart all the pants seams up to the waist. Then I just added interesting pieces of fabric from the other 2 pairs until I got a result I liked! After the pieces were all sewn together I made tucks and pleats at different places like some European designer skirts I've seen, which hopefully gives the skirt some interesting "movement".
I tested many ways and places to put the pockets and here is a close-up of the process: