Inspired Blade & Cloak & Dagger style

[Azullius Koujou]

Does the Inspired Blade lose the option of using cloak & dagger styles with Rapiers that ordinary Swashbucklers keep?

due to having "Rapier Training" instead of "swashbuckler weapon training"

if yes, could using an undersized Rapier count as a light weapon and so qualify to be used with the feat?

[SlimGauge]

Rules Reference:
Cloak and Dagger (Combat) Style

Inspired Blade

Swashbuckler

Technically, yes, as the referenced ability is replaced with another of similar effect, but different name.

[shaventalz]

Also see the FAQ on which archetyped abilities still count as the original.

Rapier Training acts similarly to Swashbuckler Weapon Training in many respects, but doesn't actually mention the original ability. Thus, it doesn't count as the swashbuckler class feature. Technically.

Allowing this interaction seems like a reasonable house rule to me, but it would be just that - a house rule.

[Azullius Koujou]

What about the option of a under sized weapon would that work?
making the rapier a ~light weapon to the user, I assume it won't work but rather than break the puzzle and start over, much easier to just replace a single piece.