I can knock a couple of those 'plot holes out for you pretty easily.

Vengence Chick (AKA Uzuki Yuugao) was Hayate's (the sick examiner who died) either girlfriend or at least close friend and also knew Kakashi as a sempai, ostensibly from his time in ANBU her role was likely to add more emotional impact to the Leaf's counter attack as well as the aftermath of the invasion.

Kurenai got pregnant because she and Asuma finally acted on the sexual tension that was always present between them, the child was likely only a means to add emotional impact to Asuma's death.