Zohaib, please remember - one request per one topic.
I'm not sure if there some existing free emoctions plugin, but you can try searching one in our Store.
Here you can find instructions on how to add moderators and give admin rights:
https://docs.oxwall.org/user-manual:privacy:moderators.
Concerning the Cron job, it seems that you have configured Cron for a few more users not including the root user. You need to delete cron command for all users except the root user.