Less important things they got wrong

Jefferson didn't know that he would be recalled in a year and a half, as he states. Instead he took a visit home intending to return when he found out that Washington wanted him for Secretary of State. He still took a while to think about it because he really preferred to return to Paris.

While in Paris he didn't just observe the birth pangs of revolution, he was helping certain revolutionaries write texts.

The early Montgolfier balloon flight with the sheep, duck and rooster was in 1783, too early for this story. He didn't meet Cosway until 1786, for example.

James Hemings worked not two but three years to train his replacement. He did apparently drink too much, but died at his own hand. Jefferson had continued to pay Hemings' wages as his chef when he worked for the president in Philadelphia.

There are some others, but they slip my mind at the moment. If you know others, please add.