Returning Player With Several Questions...

[Garlyle]

1. You can absolutely have every single Job. Think of Jobs as the "full versions" of the base classes - its not "do I want to Lancer or Dragoon", it's "My Lancer upgrades into Dragoon at 30". So, if you level every class to 30, you can have absolutely every job. Just be aware that'll take quite a while!
* The only exception is Arcanist, who has two jobs - Summoner and Scholar. You can still get both of them, and in fact level them up simultaneously, because they still use the class' level in progression - they just have some separate equipment and separate questlines for their job-specific-skill unlocking.

2. They are not presently allowed, but largely on a don't-ask-don't-tell so long as it doesn't affect gameplay. If you absolutely must use any harmless ones (such as a DPS parser), don't talk about it.

[Zerd85]

I'd rather not risk anything then.

Thanks again for the info. Looking forward to figuring out which class I want to main.

[Slatervonjager]

I'd rather not risk anything then.

That's a good outlook on things, as Square has handed out bans for use of parsers.