Breathing is normal looking to me. Or, if anything, just slightly elevated. As I would expect a nervous fish to be, really. Though I may be projecting based on what's being discussed...
That video wasn't that good, sorry. Here's a pic that better shows the state:
Yes; some spine is visible when it's turning or the light hits it from the right angle.
Managed to find some red nori at PetCo. Dropped some in around the fish, but no interest yet.
No; no pecking at anything. Occasionally "nudges" the glass, but it looks more like confusion than feeding.
I find it great that a number of us have kids of the same age. Just another thing that we have in common.