Yes, all four names are the subject of a single certificate. The certificate I can see in a Monitor expires tomorrow, but the monitor can take several hours to catch up, so if you renewed successfully today all is probably fine.
Let’s Encrypt renewals are for 90 days, a certificate renewed today should result in a new certificate which expires in December, 90 days from now. You cannot obtain certificates from Let’s Encrypt which last longer, but you can arrange to run the “certbot renew” step once per day, and each time it runs it will notice if the certificate has only 30 days or less lifetime and renew it. You also probably want to have a “hook” set to reload your web browser, something like
certbot renew --post-hook /sbin/service apache reload
But of course the exact command needed in the hook might depend on your setup. If you don’t have any experience setting commands to be run periodically like this it’s really beyond the scope of this forum.
You should be able to run
certbot register --update-registration
to change the email address which gets sent notifications