Just like bitcoin core, the RPC commands should be entered in bitcoin-cli not in bitcoind, so in your case if there's no "daemon" folder, you should find the folder containing "Zenon-cli" and "Zenond" files.
Then change the script to use Zenon-cli intead of Zenond; but before running it, run Zenond in the background.
Of course, it's best to ask a Zenon Network expert, moving this to Altcoin Discussion is recommended ("move topic" button on lower-left side of the page).
Thank you! I figured it out myself a few minutes after posting my question. Is there any chance that the incorrect passphrase is not on me but on the client/wallet.dat file itself? It really seems unlikely I got the wrong password as I wrote it down immediately afterwards and pasted it from notepad.