You should be able to swap around the keys with
xmodmap if you can't quite do it with
setxkbmap. You need the
remove Lock modifier for caps lock, as it is a 'special' key.
remove Lock = Caps_Lock
keycode 66 = Escape NoSymbol
keycode 9 = Caps_Lock ISO_Next_Group
You could place the above in your
~/.Xmodmap, which is still read at startup if the correct command is in your
~/.xinitrc, as I explain further in this answer:
However, you cannot easily mix the
setxkbmap commands, as the latter cancels out changes made with the former, as we discussed in the comments.
To execute these
xmodmap commands in the terminal to test them, you would run, for example,
xmodmap -e "remove Lock = Caps_Lock"
but you would only place
remove Lock = Caps_Lock in your
~/.Xmodmap file, as I explain further in my above linked answer.