Not a whole lot sure to the answers to all the questions, but here is what I know.
The reason AA and NW never started a low fare unit was because they never competed head to head with a low fare carrier on a lot of its routes. USAir, Delta and United all operated mainline operations at high fares and VERY high cost structures where SW moved in. They had to spin low fare carriers off in order to compete. As for CA, SW and Shuttle now coexist happily. In the begining it was an all out war between SW and Shuttle, but then Shuttle realigned flights to feed SFO and LAX and not try to be everything, everywhere in CA like Southwest is....so I guess, yes, that anwswers that one, SW won CA, UAL at one time was everything in CA and I guess it isn't now.
COLite failed because there was no organized strategy behind it. I.E. Continental never went out and dedicated a fleet of say, 737-200s at just EWR and made them "Lite". Instead CO launched Lite on a variety of different aircraft and deployed them on random routes all over the country, SFO/OAK to DEN, DEN-ORD, EWR-DCA, so there was no clear line between mainline CO and the Lite operation like there is between Shuttle and UAL. In the end, Lite was not efficient, was not catching on w/ the public and was cannibalizing CO's own mainline.
Hope this info helps.