As far as the #Fediverse 's usage of #WebFinger is concerned —

Fediverse software (including Mastodon, Pixelfed, Calckey, Pleroma, Lemmy, etc) don't seem to use the #JRD “property” element.

But if any of them ever do — since the "type" is supposed to be a URI — I think it would be better to use something like a #tagURI or something like it (rather than an HTTP(S)-URI).

Else it may suffer from #linkRot (just ostatus·org).