So I'll go through it as if it was the ORMOA setup I work with:

For the Origin, the Garlean setup isn't too bad and more or less covers the bases for story components. The biggest hurdle would be the whole "Garleans can't naturally manipulate aether" thing that bars most of them from being spellcasters, and what ones Garlemald does have are typically from lands they took.

For the Role, I've always been on the fence when it comes to Blue Mage as a tank simply because despite looking like it'd have to be a tank, not only has it never historically been a tank, but less than half of all Blue Mages in the series learned spells specifically by getting hit (most of them just had to see the ability to learn it regardless of whoever got hit). I've warmed up to it slightly over the years, but I'm still convinced that devs would rule out the Blue Mage of XI simply because almost anything in that game could tank if you built it correctly.

With the Mechanics, you really shouldn't want anything more complex than Dark Knight in terms of tanking just because of the fact that tanks usually have a lot more to worry about than just their damage rotation. I'd also recommend leveling at least one tank (preferably all three) to max level in order to get a better understanding of what a tank in FFXIV should have.

On Outfitting, the hammer is an interesting touch, and surprisingly not that much of a stretch given past Blue Mages. However, between the use of such a hammer and the whole Garlean theme, this Blue Mage doesn't seem like it'd be that much different from most ideas for the Judge job you mentioned in the lore. Also, if it's going to use a shield, it does require a different way of taking advantage of it than Paladin does, but its current state doesn't seem to take advantage of blocking at all. In fact, it's a Blue Mage; maybe that tome could make a barrier for a shield instead of having to use an actual one. The sabers would probably fit more with the visual themes the job has had before, but so would a saber or cutlass and a tome for a visual offhand.

When it comes to Abilities, I mostly agree with Mikey in that a lot of things seem either overinflated, overly complicated by tank standards, or just outright overpowered. Angel Whisper would make more sense as something like a 15 second buff that upon death resets the caster's HP to 25% of max with a 3 minute cooldown, maybe longer. If you wanted a group heal, White Wind could be something like a 400 potency AoE heal with a 1 minute cooldown (putting it in line with Equilibrium). There's some other stuff too, but this all goes back to needing to level tanks further to get a better perspective.

The overall TL;DR: It's kinda interesting, but best to keep leveling your tanks before doing more adjustments. Don't rely on your tank friend, since however knowledgeable they might be, they're still not going to be able to give you anywhere near as much insight as you actually leveling your tanks to max and doing some higher-end group content with them.