Re: Tai Sabaki
all the Okinawan styles of karate that I am aware of use it and practice it . there is a large emphasis on it in Shobayashi Shorin Ryu, and also in Matsumura Seito, both Okinawan Karate styles.
They are part of the kata from the first kata in both systems. and yes I would say they are considered Kihon, though you do develop more understanding as you train over time.
unarmed hand to hand fighting has NOT changed through the ages; only the name changes, and it has only one rule: do it first, do it fast, do it dirtiest. -- Robert A. Heinlien