^Kurn, Duras, and Gowron hadn't been introduced yet.
given that NONE of them would have existed had history not played out how it did. [...] I mean, remember, we'd all be different if just one other sperm or egg from our parents made us. If our parents even sneezed at the wrong moment another sperm would have fertilized the egg and poof - very different "you." Besides, didn't later Treks run small-universe syndrome into the ground?
The timeline was only changed 22 years in the episode's past...except for Wesley, nobody in the crew shown in the alternate timeline was so young that they wouldn't have been born yet.