Like Kazrah and Enla said, Chemist is too similar to Alchemist in name.
Apothecary sound a bit like it would be too similar to Alchemist too.
I went with Cannoneer because it was a job from a past FF game (Final Fantasy Tacitcs A2). I like bringing obscure or underused jobs into the light. I also felt like I could give it a more rugged feeling compared to the three healers we have in game, who are more these delicate mages. I almost went with just Medic for it but, at least to me, it felt a bit generic and didn't have that small nod to a small part of FF's history. :B
