These features have already been implemented in The Official Facebook Chat Plugin which is available on the WordPress repository here - https://wordpress.org/plugins/facebook-messenger-customer-chat/
It would be great to implement the guest chat as this will allow customers who aren't on Facebook to still enquire about services.
Also, the automatic pop-up as per the plugin mentioned above would also be great.
Thanks
Guest
Hello there,
Thank you so much for submitting the request!
Our dev team are doing the best they can to implement features and release updates. However, if you ever come up with any ideas or thoughts regarding this functionality, you are most welcome to add your comments.
Your help is highly appreciated!