Fix the form

Review this form for usability: <paste>

Check all of:
- Real labels above fields, always visible. Placeholders are not
  labels — they vanish exactly when needed.
- Correct input types and autocomplete attributes, so phones show the
  right keyboard and browsers can fill it in.
- Errors next to the field, in words, on blur — not all at once at
  the top after submitting.
- Typed values survive a failed submit. Losing them is unforgivable.
- Required fields marked, optional ones too if there are few.
- Submit disabled while in flight so a double tap doesn't double post.
- Enter submits.

Then: which fields could I remove entirely, or infer?