I'm not saying that NAP is better than NTP. Both have limitations. Sometimes it's not easy to distinguish what is agression and what is not or what is transgression and what is not.
Nevertheless, I'm still not convinced that NTP is a better option. For instance, if I could only stop an agression from your side by violating your property, what takes precedence from an ethical point of view? It's not really clear to me, although I suspect that putting an end to the agression entitles me to violate your property. But the opposite is true as well. In the end, transgression is a form of aggression. So, not sure this is adding anything meaninful (besides adding a twist to the NAP in order to make it even more appealing for anarcho-capitalists).
That wouldn't be a violation. At least the Rothbardian take, as I understand it, is that the use of defensive force is permitted, and not a transgression or violation (subject to the principle of proportionality). Or another way of looking at it, the (would be) violator of another's rights forfeits a measure of his own property rights when doing so.
I'm in favour of dropping that way of using the term aggression altogether, for the reasons mentioned in this article.
I'd say it makes it's a more accurate as well as more understandable term, with no disadvantages that I can think of that aren't also shared by the NAP term. That's already a big win imo.