I've found that (if I don't want SELinux), I have to do this to the kickstart.

 Do what?  Did you forget to write something here?
My fingers didn't keep up, did they :-)  Look through the package list for anything that looks like an selinux package (usually the names begin with se), remove them.  When you try to build, the list of packages will run by.  If you still see anything to do with selinux, make a note and mark it to be removed in the package.  So, if you see se_foo_bar_your_install, you would add this to your package list to remove it:

-se_foo_bar_your_install

It looks like a lot of your failures are because certain commands arn't available: sed, getent, etc.  Make sure they're installed.  Then make sure your PATH variable includes their directories.

I do have those things available... at least to me.
I don't know about the environment that  livecd-creator makes for itself though.
Same things goes for PATH.  I can execute those utilities.
Strange... I believe livecd-creator uses your PATH.

Tim