if you do a very simple alias in zsh, does it work? open your .zshrc file, and add the following line:
alias ls="ls -GpF"
after adding that line, type this line in your Terminal:
source ~/.zshrc
tell us what happens. Also, just for shiggles, make sure you are using single quotes vs. double quotes, I have seen that make a difference in the past on different versions of shells/OS/whatnot.