If this was setting up Chemist or something similar, then why do it on the First? While it's 'possible' we'd get a new job tied to the First, new jobs tend to be tied to new areas in the expansions, with the exception of SHB because it's set on another world so they drew from things back on the Source rather than tie new job lore to Norvrandt.
So any apothecary/chemist lore...would be entirely separate from this kid we talked to. I think the point of the kid wasn't to foreshadow a job so much as to just show someone else inspired to be a hero in their own way, tying into things thematically with the patch.
Spoiler for 5.3 msq.
Basically, Elidibus draws his strength from people inspired to be heroes in order to become the 'Warrior of Light' and this is providing an example of someone like that at the start of the 5.3 msq. That makes more sense to me for why it's there as opposed to them setting up a job that will probably have its roots back on the Source rather than Norvrandt if added.