Ok I'll start a little further down as first anticipated. You mention subprojects. For treason that might be a good Ideer.
In Denmark Treason was punished with ax, sword or hanging, not burning.
OFcause again the witches in Salem was hung by the neck, so there is variations. So I do believe that Treason here migt be better of in another project connected to this one of cause.
Reason for this is that burning ussually was the punishment used when it came to church matters. That also passed on into the protestant areas with the different fractions of christians. A remnant from the middleages.
So maybee the project should start with a little esplaining of why they used this method. That would or at least might clarify some of the issues here
When it comes to heresy and witches that is coing to be diffecult to seperate. Especially in the Catholic area, but also in some protestant areas it was a hair fine line that was very undefined!
Reason for this was the definition of a witch. The church wanted the wich to have sold her soul to satan.Therefor they were apostated from the one true church!
So was other christian groups as well, although they might not have sold there soul. But the definition is as said very unclear.
So the best way to go I believe is to make clear that burning mostly was connected to church matters amd ofcause problely mostly in Europe, since the Salem witches was hung, but punished for the same crime.
How this difference in execution methods is to be integrated I am not sure. BEcayse if we call it burned on the stake, the Salem withes do not belong here!
But then again the Salem withctrial comes later than many of the Eropean witchtrials.
They were mostly compiled in the timeframe of 1550-1650 and then slowly lessens as the religious fever died ot as well.
In Denmark there was a small outbreak around 1690-1700. Here they did not use burning either, so maybee the burning method was going out of fasion or what ever you would call it.
Therefore maybee some sort of time line with at least the witchtrials would be an interesting thing to add to the project, since that might show some changes in the way the trials also changed!
Selfburning is not a punishment and I believe belong more into a catagory with civil protest and the like.!
Maybee we could also have a project that descripe different execution methods and why they used them? Ok maybee a little macabre but it could be useful.
Or maybee have a little section on how it was punished in different areas. In Denmark for instance the wise woman was not executed and very rarely punished. That was different in other areas of Europe!
Sorry for writing a novel! I have some more thoughts, but lieve it at that for now.!