The ball effect choose target?

Radiance rules aren't published yet. This uses the printed card and current rules only, and it isn't a ruling on the new mechanics.

No — The Ball's play/move ability doesn't target anything. Its only choice is the modal "choose one" (Draw 1 / Deal 2 to enemy units here), and picking a mode is not a target. "Deal 2 to enemy units here" identifies its group by criteria — every enemy unit at its location — rather than a chosen object, so it doesn't target those units any more than "kill all units at a battlefield" targets them (Rule 355.10.d).

Practically that means no Deflect surcharge, nothing for a Repulse-style effect to key off, and it will still hit units that can't be chosen by spells/abilities. It's a triggered ability either way, so any targets would be locked in when the trigger goes on the Chain at finalization rather than at resolution (Rule 355.5.b) — but here there are none to lock in.

This is my interpretation based on the targeting rules and the print on The Ball. No official FAQ exists for this specific interaction.