No particular use-case in mind yet - the customer is evaluating ISE and he is trying to understand the limitation for the existing SMB switches he has.
So as I understood from your answer, the only probe we would use is RADIUS for the SMB switches. We would need the PLUS subscription in any case, correct?
It will work as well with SNMP , NMAP as well as DHCP , as I explained it wasnt tested thoroughly but in theory it should be capable . I suggest a trial and error approach and would be happy to get any feedback from your findings.
As for you license question , profiling does not need PLUS licensing , however if you intend to enforce policies based on profiles then yes you would need to have PLUS in place.