Pushing Through a Rebuke/Ward

That’s a big part of the problem. A range of “10′ Radius” is a range of 0′. If they really intend the two to be different then they should have made it far more explicit.

To be explicit, I also disagree that Rebuke (or any spell with a range of “10′ Radius”) provokes as it is 0′ range (or self – they are effectively the same except that 0′ can potentially be extended via adaptations).

The listed range also affects spells like “Channelling”. As a “10’R”, it provokes quite badly when trying to clear out minions (4+ free strikes can hurt quite a bit).

Rebuke

Range: 10’ Radius – This is NOT 0′, Self, or Melee and therefore grants a Free Strike

Effect:
All creatures affected by the spell’s initial casting must
move to the edge of the effect. For as long as the spell is active,
the affected creatures will not enter the spell’s radius.
Sustained Effect: Creatures affected must remain outside of
the spell’s area.
Pushing Through: Normally, an effected entity will do all it
can to stay away from the offending priest, but sometimes
blood lust, rage, or pure hatred will allow it to overcome its
fear. To attack, the Undead must succeed in a Mettle: Perseverance
(Re) Action Skill Roll against the caster’s Passive
Arcanum Value.

This is exactly how all the divine characters at our table have used it. The rules give the impression it should not be used as a bubble of protection like Ward against the Unnatural. More of an instant fear effect on those close enough to be in the radius. If you want the bubble take Ward against the Unnatural. (as many of my peers have)

The spell description’s wording of “the affected creatures will not enter the spell’s radius” is vague. Does “affected creatures” mean all Undead, Shades, Spirits, or Infernals? Or does it mean just those creatures affected by the initial casting? I interpret it as the former but can see a point being made for the later based on the spell’s wording. Even aside from comparisons with D&D Turning, I feel that the spirit of the rule is that it can keep the unnatural creatures away even if they had not been in the initial 10′ radius around the caster.

This is an important distinction. And seeing Rebuke is most likely a variation of 3.5 Turning then comparing it for the sake of Free Strikes is critical. Even just comparing it for the spirit of the rule.
Turning is an instant effect that only works on creatures up to a certain hit dice, and then only on a variable number of hit dice in total. It spreads out from a point centered on the caster, and effects creatures until the maximum number of hit dice have been accounted for or all creature in range have been effected. Any undead creature unaffected by it can walk up the caster unhindered and attack them.
As the rules are written Rebuke works similarly (just with a smaller range, and on more than just Undead), it does not create a bubble of protect like Ward against the Unnatural, which states “Once erected, the Ward acts as a barrier that will prevent any beings of the specified type from passing through or harming, in any way, anything on the other side of the ward, unless they are able to Push Through (see below).”
You could not walk through the halls of Ventaka with a single Turning attempt, and you can’t do it with a single casting of Rebuke either.

Keeping that mind, I too believe that Rebuke should be considered Self (’10) to avoid any Free Strikes. Mainly because it doesn’t effect creatures outside of it’s initial casting.