There are always two sides to every story...
Without knowing all the facts it is hard to offer advice. She has already contacted everybody in the world (EOO, IG, Chaps, Congressman, lawyer, chain of command...).
I find it difficult to believe TWO Sergeant's Major and a Colonel are out to crush an "E-5" for failing to render a proper greeting (I have had similar run-ins with some bone-headed Army full birds out there but this is pretty over the top even for them).
Lastly, as a point of referance since I am not in the Army; standing at parade rest and saying "Roger that Sergeant Major." as you are getting your ass chewed is likely to get yourself choke-slammed in the Marine Corps.
The proper customs and courtesies are to stand at the position of attention, answer questions with a "Yes, Sergeant Major!"; "No, Sergeant Major!"; and acknowledge orders and commands with an "Aye, aye, Sergeant Major!"
you beat me to it Alex, My thoughts exactly. before I'd give ANY type of advice OR criticism, Id have to know the WHOLE story, from whay I've seen , been involved with and know about the military, Im just guessig she may have done some things we dont know about. just guessing too, if in deed she is being railroaded there are things that can be done and it looks like shes done about all of them... now with that said the actions she has taken will stirr up some REAL Sh*T and she BETTER have her ducks in line when the time comes or it could get worse... I hope everything works out for her though....
I'll add to both of these as well...
To me, it sounds like she isn't telling things the way they played out. This may be either willingly, or she may not realize what she did wrong.
To me, being at parade rest and saying "Roger that Sgt. Major" is a slap in the face of your higher command if she wasn't told to go to parade rest. If she was, then there could be something else such as her attitude, how she looked at them, etc.
Personally, if it was me, I'd just take the Article 15. Yes, it'll mark her to some degree. But, most people will blow it off after a year as long as she doesn't screw up again or bad mouth the situation when discussing it. As an FYI, I had an article 15, and it was the first thing that's looked at, and was asked about. When I explained that I made a bad decision, and I learned from my mistake, it was usually dropped without another word.
Some words of advice to your daughter: She's in the military, and while it's changed since I was in to a "Kinder, softer, and gentler" military, it IS the military and she is in the desert after all. Suck it up, learn and move on. By contacting the people she did, she's going to find herself in a huge world of hurt for quite a while.
Best to her on it though.