On 41xx Series hardware running Cisco Firepower FTD the SNMP attributes can only be read via the Data Plane (seems a bit weird but doc does say that).

But the problem is the configuration can only be read (and only read if managed with an FMC) via the Management interface

The feature request/idea is instead of a fixed drop down list of IP addresses is if can you select the device name with a field to enter the IP address and/or a drop down of populated values. This IP then gets associated with the device for rule fetching so you have one IP for fetching SNMP attributes and another for the rule base