I feel obliged to mention something about the descent. We tried to follow the E Ridge to the Mendel/Darwin col. This is not the correct way to go. We ended up having to do some rappels to get down off the E Ridge to the Darwin Glacier. I think the correct way to go is to head down off the ridge via some 3rd class well before the col. Maybe someone who got the descent right can offer some specifics?
Just wanted to mention that Lamarck Col approach is the best way to get to the Mendel Couloirs. There is now (2015) good use trail all the way to the Col, something we could only dream off in the 80s. Start at the North Lake TH. Take the Lamarck Lakes branch off Piute Pass Trail. The correct way to cross the Lamarck Col is on the extreme left side as you look at the Col(the whole saddle). There are many incorrectly drawn routes up the Col on the Internet. Again, the extreme left side by a small triangular peaklet is the correct way to cross the Col. Class 2, snow/ice of the snow field can be easily avoided by boulder hopping.
BTW Regarding the above descent comment, I have rapped off the back side of Mendel to the slope above the closest (small) lake at the base of Mt Darwin. If I remember correctly, there were three 25m raps to reach the terra firma.