Two Gun-Using Job Ideas

[Mimilu]

Not really. In the JP version of FF Tactics Chemists are actually アイテム士, or "item user". Could have called it apothecary or medic, I guess.

I was originally going to call Musketeers "Medic" but I liked the name Musketeer more, a Medic could have any weapon, were as a Musketeer has to have some form of Musket. Plus, Musketeer has been floating around since 1.0.

They could still just call it Chemist. It wouldn't really bother me honestly, the two are meant to be similar to each other anyways. It's not like anyone is going to get confused by the two really.

It's not that it would be confusing, it would just be weird that Chemists can fight but Alchemists can't.

As for the OP's ideas, the 'Fusilier' class is somewhat redundant - why not just have Musketeer dual wield guns and thus role the two classes in together? In fact, the class icon for Musketeer that's been in the game in the Coral Tower since 1.0 actually shows dual pistols, and there are numerous npc MSKs in the game who dual wield flintlocks - Merlwyb is the obvious example.

I just didn't like that Musketeers used Flintlock Pistols and not actual Muskets. We haven't had any official verification that the few NPCs with the flintlock pistols are or are not Musketeers, so I figured I'd reinterpret them (plus, watching Merlwyb in action, can you really see her as a healer?).
Another reason I designed them the way I did was what roles they filled, Fusilier is a true ranged DPS (versus Bard, who is more support-based), while Musketeer is a TP-and-skill-using healer, trying to design a class that could cover both of these roles would be tricky and creating a DPS from a Healer or vice-versa would have a lot of problems.