Please fill out the fields below so we can help you better. Note: you must provide your domain name to get help. Domain names for issued certificates are all made public in Certificate Transparency logs (e.g. crt.sh | example.com), so withholding your domain name here does not increase secrecy, but only makes it harder for us to provide help.
the shell variable $RENEWED_LINEAGE will point to the config live subdirectory (for example,
"/etc/letsencrypt/live/example.com") containing the new certificates and keys; the shell variable
$RENEWED_DOMAINS will contain a space-delimited list of renewed certificate domains (for example, "example.comwww.example.com") (default: None)
They might. The certbot renew command acts on all the renewal conf files in /etc/letsencrypt/renewal folder (one at a time).
Any options on the renew command override the ones in every renewal conf file. If they are all the same options then, sure, no problem just unnecessary.
But if you used some other method for other certs then those renewals will fail or your renewal conf will be updated with options differently than intended. What happens depends on the exact combination of options in the renewal conf and the renew command line.