Real useful, hard to understand the details.
Access control and config
See /etc/snmpd/snmpd.conf. This is where you allow/restrict access and can control what is presented. If only you could figure out the file.
Log Level control
Logging is controlled on the command line, see the logging options in snmpcmd man page The actual file to change is /etc/sysconfig/snmpd.options or /etc/snmpd/snmpd.options where the line
OPTIONS="-LS 0-4 d -Lf /dev/null -p /var/run/snmpd.pid -a"
has the necessary magic. See /etc/init.d/snmpd for the defailt.