Any Scottish posters heard of Tyree as a name?
Yes, it has been used. 64 times since 1971 to be precise, either as a forename or middle name, mostly for girls.
I'd always assumed it was a "unique" spelling if Tiree of which there are slightly more, having been used 105 times in total from 1958. Again more popular for girls. With boys it is sometimes used along with another island name, e.g. Arran or Coll.
Sorry to sound like a nerd, but hopefully that answers your question!