Also the Properties for the mordent will only give me a sharp when Interval below is selected and set to 3 (instead of 1, which would make more sense):
What is going on here? How can I get the sharp to appear above the ornament?
IMHO the manuscript is confusing, whereas Dorico’s version is clear. It is an inverted mordent and the accidental modifies the lower note. Reading at speed, if I saw the MS version I would probably play a normal mordant with a modified upper note by mistake.