The Freelancer is the singular new job added in the 3D remake. It's not a particularly impressive job; The differences in storyline result in the Inner Sasune section of the game acting akin to a prologue. The Freelancer is equivalant to the Onion Knight of the Famicom version narratively, in that the protagonists start as Freelancers until they are summoned by the Wind Crystal after defeating the Djinn. They can also be considered weaker Red Mages in that they are also versatile in their weapon choices and have access to magic, at least early on.
Freelancer is a recurring job throughout the series, introduced in Final Fantasy V where it had a similar role. However, V's freelancer functioned somewhat more akin to Onion Knight, as mastered jobs would have their stats added to the Freelancer as well as the job having two ability slots to almost every other job's one. III DS' Freelancer doesn't have any particular srengths aside from good armor selection and unlike the Onion Knight, their stats don't explode to suddenly make them top of the class. The most they have going for them are their access to late game weapons and the Celestial Gloves (the job mastery item which increases their stats by 15; Much like the Red Mage's Crimson Vest, these can be combined with Excalibur and the Ultima Weapon to create a significant boost in stats)
The Freelancer job features Luneth, Arc, Refia and Ingus in their default outfits.
Freelancers have access to the very first tier of magic and access to both types. Like much of the Freelancer's kit, it works to carry them through the early stages of the game, but will fall off the further in you go.
The guide emphasizes that the Freelancer should be swapped out of as soon as the first batch of jobs are unlocked: The only real benefit the Freelancer has is a relatively sturdy defense due to their access to a lot of armor options. In terms of magic, their cures won't keep up late in the game and while multiple Cures can be useful out of battle, they only have 20 casts of magic; Meanwhile, their attack magic falls off hard due to doing less and less damage to later enemies. As far as equipment, Freelancers have good armor choices, but are limited in terms of weapons until the endgame.
While using Freelancers during the opening of the game, the guide recommends taking advantage of their versatility by assigning them different weapons/roles with two frontline and backline fighters.