we are having the need to change our RADIUS, SNMP and super passwords regularly for all switches (ICX7150) and APs.
Is there an easy way to achieve this? We are not that experienced with the SmartZone and its capabilities.
Also is it possible to easily tag all LAGs with a VLAN?
Take a look at the CLI templates feature. I believe you can achieve this by creating a template with these commands and then sending it to the desired switches. CLI Templates Documentation
As a good practice, try it first on a few lab switches and validate it by accessing the switches through SSH and checking the running-config. Then you can apply it to all your switches.
Also be sure that you are running a switch code that accepts all configuration changes through SmartZone.