snmp is working, installed today the addon, but it gives me totally no valueable information (yet)
no eth0, no memory, no disk .. so it seems some basic features are not enabled or not available (dunno why yet)
for temperature and other stuff the basic /opt/vc/bin/vcgencmd measure_temp commands could be used
see also here
Monitoring with the Raspberry Pi
I tried to use the pass function with the snmpwalk on my observium instance but no further info was passed to snmpwalk
unfortunately the addon also does not have snmpget to see if things could work fine.
if there is any progress I would like to test 
also it seems that some mibs you want to use (CPU, Memory etc) are missing from the configured folder
net-snmp-config --default-mibdirs
/storage/.snmp/mibs:/storage/.kodi/userdata/addon_data/service.net-snmp/share/snmp/mibs
there is no ../share/snmp/mibs folder