Bill,
I'm coming in during the middle of this thread, so pardon me if
my comment has been already made or discounted.  I've found
that one of the best tests of a conjunctive adverb is that it,
unlke subordinating conjunctions in general, can't be moved around.
'albeit' and 'though' can, but I think that nonetheless they haven't
gained widespread acceptance as conjunctive adverbs. That is,
they haven't reached the convention status yet.  They seem to
reflect the problem that we often face w/ grammar--the fact that
so many words fit on a continium of being this part of speech or
that part of speech, rather than the neat categorical way of
thinking that we like to use when describing language.

In some ways, then, I'd call the sample sentences stylistic problems
rather than grammatical errors.  They are defensible grammatically
as conjunctive adverbs but probably aren't the best choices for
the student's writing situation, given the fact that we are having
to have this discussion in the 1st place.

That's my humble take on it anyhow.

larry beason