8 am? That sounds quite reasonable if you are just hiking to Trail Camp. NO WAY are you going to make Trail Camp in time to summit and return, unless you expect to get back to your camp about midnight.
Are you sure your other member is talking about summiting on the first day? He's probably thinking about summiting on the second day.
After carrying overnight gear to Trail camp, most people are done for the day. Unless your group are all in extremely good condition, your plan will not work.
You are correct about going down the chute late in the afternoon.
