How odd. But, well, it's good it's not Chiari! Did he let you know of any treatment for the herniation?
Loose knees, back pain, lax ligaments, popping/snapping sounds (this could be indicative of subluxing joints - my doctor told me that's a lot of what my joint popping/cracking is about, especially if I feel things jolt back into place), etc. the herniation is also linked with things like EDS (I'm not a doctor though! But Chiari is common in EDS). Early onset POTS is also common in EDSers because of different etiologies (we don't have POTS because of viral infections or things like that).
I dunno, I could be wrong, but yeah, a lot sounded familiar to me.