Interesting idea, and not without merit, but still something of a houserule. According to the book the considerations that factor into a Catch are researchability and accessibility.
Three things actually.
1. Scope (specifically against or all but).
2. Ease of Access to catch.
3. Awareness (researchability)
While I do mention the difficulties of weaponizing living mortal flesh, it did not factor into my opinion of a +2 catch value. On scope, it protects against all but living mortal flesh (+0). Living Mortal Flesh is very common (+7). Without knowing where the protection came from, I conclude that this is an effect specific to one individual (+0).
If this person is from an famous order of monks, then yeah I guess there can be some knowledge of it. But otherwise, how is anyone going to know that a bare fist is the best way to hurt someone? How often do mortals get into fist fights these days? Other than bar fights, school, prison, and Hollywood?
Even if you face a lot of mortals, who goes for fists when baseball bats, chains, lead pipes, and axe handles are legal to own?
However, "living human flesh" is a pretty burdensome catch since even the mere presence of the catch is supposed to make a person uncomfortable (triggers compels). So even if someone took a generous perspective of "other people's living flesh" you basically have a character that doesn't want to make direct physical contact with others. Hello Mr. Monk.
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As to the A-Minor chord catch. Technically the sound would trigger a compel of some sort. Either costing a fate point to avoid it, forcing retreat, or some sort of psychological break (take out). Maybe even force you to try to attack the source of the sound.