Re: Question about Aikido (Ki-Aikido)
Believe your first question is really what ushiro waza is all about.
On the subject of kicks, Mitsugi Saotome-sensei spent an entire class on kicking techniques and defenses at this year's Summer Camp in the Rockies (boy, were my thighs sore after that!).
At camp, we also worked with Frank Doran-sensei, Hiroshi Ikeda-sensei, and many other high ranking aikidoka who showed the ability to use devastating punches, elbow strikes, palm heel strikes, knees, and other other atemi in the course of an engagement. All the strikes are inside the various techniques--it's part of the student's job to recognize them and determine when they're appropriate.
Perhaps the real trick in our form of budo is to have all of these capabilities available, AND to know how to manage the engagement in such a way that we won't have to use them if an attacker gets the message of his vulnerability soon enough.