Hi,
It looks indeed like the EPS translation routine use by JMP is buggy: it replaces fonts with irrelevant alternatives.
I don't have a perfect solution but here are 3 workarounds that may help:
1) JMP PDF -> Illustrator: the cleanest approach, although not perfect, is to save your graphs as PDF files: these can be directly open in Illustrator with the caveat that the font names used by JMP may not directly translate to the fonts recognized by Illustrator (e.g. JMP "ARIAL" is not recognized by Illustrator as "Arial" and needs to replaced)
2) JMP EPS -> Illustrator: In Illustrator, select the entire graph, go to Type > Find Fonts and then replace Helvetica back to Arial: it might be tedious if you have a lot of plots to edit but this will preserve all text as editable entities
3) JMP EMF -> Illustrator: within JMP, save your plots as EMF files which will maintain the font for all horizontal text but the vertical text will be converted to paths which are not editable entities; this will require to recreate the vertical text manually = not ideal either.
Best,
TS
Thierry R. Sornasse