If you are running gateways/analytics separately to the manager components, trawler should be usable without the cloud manager in the cluster - you can turn off or remove the 'manager' section from the nets portion of the configuration.
Trawler requires a password to connect to the Datapower instance. Can I create a separate account for this?
Yes, a specific account can be specified for trawler to use. The intent is for trawler to only need read-only access, however currently there it is also attempting to enable statistics - which needs to be switched to check for statistics - issue.
Yes - this is how trawler is collecting the metrics.
I intend to build this up gradually - there's no additional documentation yet, but I'm happy to take questions / suggestions either by e-mail or on the github repo. Hopefully then we can focus documentation on the areas that are most useful first.