If I hold a Battlefield with Allay Eager Admirer, and I have Ornn, does he have 3 Deflection instead of just 2?

Yes, Ornn would have Deflect 3 in that scenario.

Here's the breakdown:

• Ornn, Forge God has printed Deflect 2.
• Allay, Eager Admirer grants Deflect (value defaults to 1 per Rule 809.1.b.3) to your other units at its battlefield.
• Per Rule 809.2, Deflect values from multiple sources sum together.

So Ornn gets his own Deflect 2 plus the Deflect 1 from Allay, for a total of Deflect 3 — opponents must pay 3 Power (any domain) to target him.