Interesting about the hoatzin, one of the most primitive birds, and one which seems not to be closely related to any other living bird. The wing claws are found only in the young bird, and persist only for 10 weeks. It looks very much like a case of ontogeny recapitulating phylogeny.
Ostrich wing claws are modified feathers and not in any way homologous.
Baby birds are born with a tooth like appendage that helps them get out of their shell, so they must have the genetics to form teeth.
Ever seen a chick 'egg tooth'? Know where it is?
http://www.owlpages.com/species/bubo/virginianus/greathorned12.html
And, a bony tail could be just a micro-evolution adaptation of a creature or some strange genetic mutation.
All Archaeopteryxes have them, so it's not a simple mutation of one individual.
Buit more broadly, your post fails Occam's razor. The simplest and most compact explanation is that Archaeopteryx is a transitional form. You can always argue that all of its reptilian features were secondary adaptations; but no living bird shows wing claws in the adult derived from the hand bones; no other shows teeth in the jaw in any way homologous to reptilian teeth; and no other has a long, bony tail.