We chose to rap the first 3 pitches, the 4th and last pitch over the icy rock bands we felt we had to rap. One of the guys in our party downclimbed the first 3 pitches. If the snow was firmer (we stayed on top a long time) I might have downclimbed. But since there were rap stations already setup (webbing with a rap ring around rocks) it made since to rap and avoid the added risk.
Conditions will probably be very different when you go. I'm sure there will be no snow on the lower rock bands. The top and steepest part of the final 400 could be free of snow too.
IMHO: Going by what you said and the conditions we experienced, this does not sound like a good route for your group. Maybe conditions will change a lot by the time you go and maybe others with more experience on Whitney have other opinions or advice. The final 400 is not technically hard, but it is mentally hard because of exposure and steepness. I think a group needs to be comfortable with exposure and 50 deg+ slopes to be successful.
If you don't rappel I'm not sure what good gear will do you. I guess you could top belay people down but a redirected belay off an ATC guide or grigri is more difficult than rapping. Get some rap experience, rap double strand and tie knots in the rope ends so you can't rap off the end.
I'm curious what others think. Hope you have a successful and enjoyable trip!
