How does the 5th (and higher) level Unchained Rogue Skill unlock for the Intimidate skill would interact with the Taunt feat?

Question

How does the 5th (and higher) level Unchained Rogue Skill unlock for the Intimidate skill would interact with the Taunt feat?

All of the likely interpretations lead to weird results,

a) If you rule that the skill unlock applies whenever I use the Taunt feat, then it follows that it's possible for me to unlock the Intimidate skill's extra abilities with 5 ranks of Bluff, even if I have zero ranks of Intimidate, since Bluff would be doing it's job. This doesn't seem right, and violates the text of the rule, but this is still a fairly sensible interpretation of an unusual situation, since the feat specifically references the Intimidate Skill to describe what it does.

b) If you rule that the skill unlock requires 5 ranks in Initimdate to open, then I end up activating the Intimidate Skill abilities at a time when I'm actually using Bluff. This actually seems like the Rules-As-Written interpretation, but that doesn't make it any less strange.

c) If you rule that I can't use the skill unlock at all while using the Taunt feat, then you're gutting the text of the feat itself, which states "You can demoralize opponents using Bluff rather than Intimidate (see the Intimidate skill description for details)."

I think all three answers lead to fairly odd outcomes, so there's no sensible way to decide between them other than GM interpretation. Thoughts?

Answer 1

RAW

Option b).

Rules As Written, even using Bluff to demoralize a target would benefit from Intimidate Skill Unlocks, if you have chosen Intimidate with Rogue's Edge. The verbiage is:

If you exceed the DC to demoralize a target by at least 10, it is frightened for 1 round and shaken thereafter.* A Will save (DC = 10 + your number of ranks in Intimidate) negates the frightened condition, but the target is still shaken, even if it has the stalwart ability.

Nowhere does it say you need to use Intimidate for that demoralization.

But slightly more opinion-based:

It seems really suboptimal to pick Intimidate as Rogue's Edge skill while also picking the Taunt feat - which would seem wasted to me. Possible exception if you have some high bonus to Bluff which you don't have to Intimidate, and really consider demoralization that important. And it's not like you can skip investment into Intimidate that way, since you need the skill ranks to actually unlock the special boosts.

And sure, it lets you negate the size skill check penalty, but generally I find better things to spend my feats on.