Bash – Why are these aliases failing

You shouldn't define aliases in /etc/zprofile or ~/.zprofile. These files is only loaded in login shells (“shells” meaning zsh of course). The proper place to define aliases is in /etc/zshrc or ~/.zshrc, which is read by all interactive shells.

To run zsh without loading /etc/zprofile, just run zsh with no option. The option -f tells zsh not to read configuration files at all, but since you want to read your alias definitions, that's not the right option. Since /etc/zprofile is only read by a login shell, just don't pass the -l option (and don't set a zeroth argument that begins with a dash).

Zsh has no option or environment variable to read one extra file on startup. If you want to prepare for that, you can add eval $ZSH_EXTRA_STARTUP_CODE to your .zshrc.

You can set the ZDOTDIR environment variable to make it read all of its user configuration files from a different directory, e.g. ZDOTDIR=/tmp/foo zsh reads /etc/zshenv, /tmp/foo/.zshenv, /etc/zshrc and /tmp/foo/zshrc. So to export aliases from the current instance to a child instance, you can run something like

tmp=$(mktemp -d)
alias -L >$tmp/.zshenv
echo ". ~/.zshenv; unset ZDOTDIR; rm -r ${(q)tmp}" >>$tmp/.zshenv
zsh

1. Aliases are expanded when a function definition is read, not when the function is executed …

   $ echo "The quick brown fox jumps over the lazy dog." > myfile
    
   $ alias myalias=cat
    
   $ myfunc() {
   >     myalias myfile
   > }
    
   $ myfunc
   The quick brown fox jumps over the lazy dog.
    
   $ alias myalias="ls -l"
    
   $ myalias myfile
   -rw-r--r-- 1 myusername mygroup 45 Dec 13 07:07 myfile
    
   $ myfunc
   The quick brown fox jumps over the lazy dog.

   Even though myfunc was defined to call myalias, and I’ve redefined myalias, myfunc still executes the original definition of myalias.  Because the alias was expanded when the function was defined.  In fact, the shell no longer remembers that myfunc calls myalias; it knows only that myfunc calls cat:

   $ type myfunc
   myfunc is a function
   myfunc ()
   {
   cat myfile
   }

2. … aliases defined in a function are not available until after that function is executed.

   $ echo "The quick brown fox jumps over the lazy dog." > myfile
    
   $ myfunc() {
   >     alias myalias=cat
   > }
    
   $ myalias myfile
   -bash: myalias: command not found
    
   $ myfunc
    
   $ myalias myfile
   The quick brown fox jumps over the lazy dog.

   The myalias alias isn’t available until the myfunc function has been executed.  (I believe it would be rather odd if defining the function that defines the alias was enough to cause the alias to be defined.)