You think you were off? The first time I saw artwork for Kid, I assumed that she was the daughter of Crono and Marle. Artistically, it's hard not to come to that conclusion, what with the hair and the spunk. Kato really threw me for a loop.
I don't much like the idea of immaculate conception for Crono. That plot device feels a little overused to me. Crono shouldn't be the center of the universe, but rather one essential part among many. Chrono Trigger I think works best as an ensemble.
Kid? Well, can't say I see how would one make that conclusion, but then again, I used to believe in the 'Miguel=Crono' theory for quite some time so...
Anyway, yeah, I agree on that about Crono. In fact, when you look it this way, reviving him is something you're not actually forced to do. Sure, the story clearly directs you that way, but at this point mostly everything you need in preparation for the final battle is already at hand. The sidequests only needed the Winged Epoch for access, the Black Omen is already there, etc.
I'm not saying he's not important to bother reviving, which, in fact, is clearly not true considering the Time Egg working and Gaspar's words; but when you do, he's no longer forced to be in the active party, he can even miss participating in the final battle, so yeah...