“Did the crossing contain tactile paving?”
Not that I recall. It appeared to be just some narrow white painted stripes, likely by the College, rather than TTS.

Though, I surveyed this quite some time ago, so wouldn't rely on my recollection. A re-survey would be better.

“Signposted as a 'marked crossing'. It isn't a zebra crossing under Jersey law since it lacks studs, give way lines and a controlled zone.”
Your knowledge of the legalities exceeds mine. Which legislation are the criteria specified in? I would guess the Road Traffic Act.

Though, the wiki recommends using generic values for the crossing key, and using crossing_ref for the weird names which we Brits (and/or Beans) call them. Our names for them have no meaning elsewhere. But a non-controlled (I can't recall the correct value string) crossing makes semantic sense without needing any local knowledge.