How were Ben Franklins "positive" and "negative" assignments passed down through the years?
Franklin arbitarly named two things.  And since they summed to nothing, it made sense to use names that were suggestive of surplus and deficit, such that they cancel out. 

There was no way to know which was actually "gaining" anything and which was "losing" anything. He assigned them completely arbitrarily. 

He made a list saying which material went positive and which went negative when you rubbed them together. Others added more material interactions to this list. For consistency the terms had to remain the same. Changing them would have been like changing North for South. Why? 

Fast forward to the modern day. Many people believe Benjamin got it wrong because current is the opposite direction to the movement of electrons in a wire. They believe that an excess of electrons happens only by gaining an electron, hence electrons should have been positive. 

That is off course a complete misconception, as you could also say the addition of a positive charge results in an excess of protons, hence protons should be positive. 

The reason people are confused by this is they mostly deal with currents of electrons (in wires) and don't understand that there are currents of protons (such as in water, batteries, fluorescent lights, etc.). 

Putting together a detailed chronology is hard because at this point in history electrostatics was extremely exciting and easy to experiment on. Experiments would be repeated by hundreds of scientists all of the world. There was a real sense that they were closing in on the power of God With these magical shocks. Even common people could repeat the experiments. 

Try starting with names like D.Gralath, J.Allemand, G. Monnier and of course L.Galvani. These guys often quickly repeated and built on electrostatic experiments, reusing terms including Franklin's. 

It would be a huge undertaking to track usage. Probably require figuring out where Franklin's work went and who would have read it first and published experiments based on it. 

(You get the impression from Volta that it was already a well understood convention to use the same names as Franklin).