I have received a PM with a suggestion that I believe worthy of discussion.
RealXtend
I've had a quick look but it does look like an option. The Wiki for RealXtend has two stubs one for importing Blender and One for importing Studio3DMax unfortunately they are just that stubs with no content.
RealXtend has Avatar creation and while it appears not to have the same look/feel as an Uru age it may be possible to bend it to our needs should there be a decision to go that way.
I have looked at a few suggestions in the past and to me this one looks the best so far.
In a perfect world we would have used the Alcugs development if it was still available within the rules (I believe this is blocked on two counts 1)reverse engineered and 2)Subject to the authentication server shut down).
I remain open to suggestions.