If you get your Cisco IOS, WLC or AP data from syslog or raw text files you can use the Cisco Networks app. If you already have this data normalized in a database table, you can import it to Splunk using the DB connect app. You'd probably have to alias a lot of fields to get it working. My question is why do you want to use Splunk if you already have the data in a database? Splunk is really good at raw text in, formatted data out.
As for the other data types you mentioned the Cisco Networks app will not help you. Try searching for the technologies you want to get into Splunk at apps.splunk.com to see if you can find anything that will fit. Most of the apps and technology add-ons are quite well documented.