Well, actually, Schala DID fuse with Lavos. Otherwise the Chrono Cross wouldn't have been needed to free her. When she created Kid, then she was not, but immediately thereafter she was.
Now, as for the topic... yes, actually, that irony did dawn upon me at one point. It was the reason I had Schala say in my fanfiction: 'What strange chance that was it that I, alone of all my kin, should have borne the judgement of God for the sins of my people. I, who at risk of my mother’s cruel and terrible wrath spoke out against our unholy quest for immortal life. Yet I was the only one to achieve it, and finding that which I never yearned for, found it a curse beyond your reckoning, yea, beyond the reckoning of any mortal.'