Adrian Wenner  said

 " I won't pretend to be able to answer all that was asked but can provide
some insight. "

and

    "However, I cannot comment about the correspondence between the poison
sacs of stingers and where they might have come from."


 In fact,  nobody has seen the 'evolution' and we can only hypothesize
about what 'might' have happened.  If the honey bee stinger were a part of
the ovipositor, why does the queen not use the stinger as such - especially
since egg production is her purpose in the hive!