Nu, nu. So I’ll make heter iska on all of them.
Expect many Shevuos. Besides, it would be questionable who is the Tovaiah that would be Mechayiv the Shevua.
The market was spiraling on itself, but it was just panic–not actual decline in value.
Meanwhile, the banks were forced by regulation to deleverage, and they were doing that by dumping assets which further exacerbated the problem. They really should have done that by raising more capital, but, for complicated reasons, it didn’t make sense for the banks’ equity holders to do that. The bailouts forced them to deleverage by raising capital.
I’m not sure where you are going with this, but the strong firms (such as GS) were able to raise private capital. It makes more sense to raise capital than to lose your shirt.