Read Brett Williams' story...
http://www.mountwhitneyforum.com/ubbthreads.php?ubb=showflat&Number=106198#Post106198His group was 1st Timers who did it right.
3) No, but I'd bet you can get an overnight if you want one...
4) You should carry enough gear to keep you alive should you get caught out, or have an accident...
The permit is for 12:00am, but the FS usually cuts people slack if they need an earlier start.
You need to know what your pacing is going to be...and as Doug always says...Slower Is Better...so you don't burn yourself out.