If more than one produced by a Lapis Orb of Dragonkind is spent to cast a single Dragon creature spell, the delayed triggered ability associated with each mana spent will trigger. You will scry 2 that many times.

The mana created by Lapis Orb of Dragonkind can be spent on anything, not just Dragon creature spells.

The delayed triggered ability will trigger whether Lapis Orb of Dragonkind is still on the battlefield or not.