Don't bet the farm on numbers you see in Yahoo profiles. The information is wrong or hopelessly outdated far too often to be considered reliable. Pearlman and Frame, who are no longer with the company, were the only insiders with a meaningful amount of stock. Both had been dumping stock for a year before leaving the company and there's no way to tell what they've done with the remaining shares since then.
The Yahoo numbers include millions of options that are so far out of the money there isn't a chance in the world they would be exercised. There is/was a couple of 5% institutional holders, but I wouldn't treat that as being on par with insider ownership. Especially considering Chapter 11 would pretty much void the pending shareholder actions against the company. The derivative action might fly, but that would just put a few extra bucks in the creditors pockets.
Insiders still with the company own around 1/2 of 1% of the outstanding shares. And, in answer to your first question, yes, shareholders are left with an empty bag after most bankruptcies. Not a lot of downside for insiders, but Mellon Bank and Dimensional Fund got clobbered pretty good.
I don't know what kind of business plan Dimensional Fund has, but it can't have anything to do with making money. I don't think I've ever seen a good pick from them, but they do seem to have a lot of Seitels to their credit. I've even seen then try to average down AFTER Chapter 11 was filed and the assets were about to be sold off to cover DIP financing. Oooof!!!!