IP SLA monitors are configured via CLI manually or NetConfig, rather than through IPM itself, can it pick those up for reporting only?
Yes. By default, IPM does not push the collector configs to the running config. You can enable this by checking the "Copy IPSLA Configuration to running-config" box under IPM > Admin > Application Settings.
Not unless you specify "life forever" as well. Else, it will only be active for 3600 seconds.
No, it really wasn't successful. While eight collectors were found, none were imported. The operation status of the collectors is 5 (inactive) where as IPM is expecting either 1 or 6 (reset of active). Check the rttMonCtrlOperState for these collectors, and you should see they are not active. Define a new, active, collector, and IPM should be able to import it.
In IPM 4.1 and higher, you can import collectors from devices using the ipm importcollector CLI command. Once the collectors are imported, you can run all the usual reports on them.