If the trail is clear of snow, I think it is very easy to follow, even in the dark. The one exception would be a short section of the trail above Mirror Lake. I'd leave the flashlight at home. Get an LED headlamp. It will be well worth the $50.
If you have never used an ice axe, you should probably turn around if they are needed. You won't know the trail conditions until it gets closer to your hike date. If the switcbacks are open, no ice axe necessary.
While not an absolute, I doubt you will need chains.
I got altitude sickness the first time I was on the whitney trail. It kicked in around 12,500' and it was debilitating. You really need to acclimate if you want to be assured that you won't get it. But then again, some people are more susceptible than others. Diamox can provide some relief.
Personally, I'd leave the radios at home.
