The gunsmith would be acceptable, albeit most would likely consider him/her crazy for risking the 'curse'.
As for magic artifacts, I'd strongly advise against anything like that. With magic's decay, I think we'd prefer most magical items to be left out unless it's a major plot devise that we're implementing.
I'm quite hesitant when it comes to gunsmjths. I'd need to see a character sheet or see what your plans are for them in terms of how they are personality and history wise and how you're going to write them. If you do choose a gunsmith character I'd strongly ask that you read up on the established canon with regards to dragon powder and the like.
We are totally fine with blind characters!
And feel free to bring in an older character! Just make sure they'd fit into the story and setting.
I'm going to say no to magical artifacts. I'd prefer magic to be only with humans rather than objects. They could have a lore to the objects, a sort of placebo or con, but I'd prefer to stay away from magical artifacts.