Seemingly an absolute ton, like every 1-2 chapters there's a choice with divergent outcomes/battles. But not all of them are far-reaching; some will probably only make for a single different map.
From preview material, we know of:
* A short route split before the demo portion, where the player can choose to tour either Hyzante or Aesfrost with Roland and co.
* The demo's route split (Surrender or Defend Roland), which seems to have far-reaching ramifications.
* In the very next chapter, there's another route split for
both the Surrender
and Defend Roland paths. One of these seems like it could be a 1-chapter split, but the other... kind of doesn't, from what little we know.
Plus
several other Scales of Conviction choices we've seen happening but have no info on.
1. You can.
2. There doesn't appear to be a freeform job system akin to FFT/TO. However, there does seem to be job promotions for each character later in the game, and there's also a skill tree for their weapon, which was shown in Famitsu:
