I have the Kokatat Bibs and love them. I don't find it hard to mate them with my drytop also a Kokatat.
The Tropos don't insulate as well as the Gortex, so if you get those make sure you still have layers. In the spring I have a custom made micro-fleece bunny suit, in the summer I have polypro pants.
You can get the Tropos bibs and send them in to Kokatat, they will put in the relief zipper for another $100 or so, or get the Gortex bibs and be done with it.
Tropos - Kokatat Watersports Wear - Women's TROPOS Whirlpool Bib
Gor-tex - Kokatat Watersports Wear - Women's GORE-TEX® Whirlpool Bib
On the waders... without seeing them I'd be very careful. The last thing you would want is to have her swim and have the waders fill with water and sink her. This is why you won't see dry pants with booties.