Best job for soloing/low manning pre-Abyssea content

BST dominates most 75-cap content due to the way level correction works for mobs (i.e. skewed heavily in the lv99 pet's favor), so yeah, that's probably the best way to go. Pet also has far better survivability than we do; for the most part players are still fragile to a lot of things. Like, it wouldn't surprise me if most old mission-related BLM mobs such as the orc in the house at the center of Davoi will probably still be able to knock out 1/3-1/2 of a player's HP with a single nuke, but a lv99 BST pet will probably not even take 3-digit damage from it.