Excellent work! I've been wondering how the official timeline fits and it doesn't. Nobody heard the glass being shot out, some said they let Lanza in. I tend to believe that.
9;35 call from school
9:38 cops supposedly make it there yet shooting doesn't end until 9:42 - 43?
5 minutes from their arrival and only 2 doors down the hallway and they haven't seen him? No cop said they saw Lanza alive.

I got a screencap of a hole shot through Rousseau's class window but only 1. So how did those cars end up with bullet holes? There must have been a firefight outside of some kind, at least a few shots fired.

Lanza supposedly did all this:
Shot in the front glass
Shot Hochsprung and Sherlach
Walked in to the office and looked it over
Shot the woman in the arm and leg trying to hold the door (room 9)
Shot another woman in the foot in (room 1)
Banged on several doors and kicked a few.
screamed obscenities while walking around
Killed Rousseau and 14 kids
Killed Soto and 6 more kids and a teachers aide and probably had to change mags or gun jammed for kids to make a break and run.

Now, the 6 kids who ended up at Rosens were from Soto's class and they had to have made it there before the cops arrived (Barb Sibley saw them the cops didnt)

It's 400 yards to Rosens house - 2 minute run. Add that to the 6 minutes after cops arrived means that 8 minutes after Lanza shot Sotos class there was shooting still going on.

That alone is longer than the OS says he was inside shooting. My guess is he was in there close to 15 minutes.

I think Lanza was a patsy and suicided on the spot while the other 2 or 3 ran. 1 got caught on crestwood, the other 2 went to the woods where they caught 1. Cops were searching 6 Riverside dr for a suspect which is right behind those woods. This is where the purple van comes in that may be connected to Aaron Greene.

I could go on but as you can see there's so many contradicting testimonies and timelines that it's near impossible to establish anything.
All the same I commend you on what you've put together. I just think there is much more evidence that needs to be put in the blender.
Cheers.
Bitter