Before someone says I have Firefox/Chrome on my iPhone; they are just skins for Safari. Same vulnerabilities which exist on Safari(Webkit) can be exploited there as well since they aren't allowed to use their browser engine.

If I understand you correctly, "open source" is not a kind of openness and should be disregarded. Assuming that is so, for the sake of argument, what does count as openness?

Sure you can't. That's not Firefox, but Firefox-branded Safari.

You can run real Firefox too, if you jailbreak first.