Hi Scott,
What you stated is correct, there is an LTI with Starfish to Canvas where you can SSO into Starfish without leaving the Canvas environment, as well as it does pull in course information like grades and logging in information.
What you may not be aware of is that you also have to have their "data pump" application installed locally so that it can pull the CSV files you have to create from data out of your SIS and have to put in a specific file location so that "data pump" then will pull on a nightly basis to import into Starfish.
They do not offer any API's like Canvas and therefore if you need to make changes it can be a rather lengthy wait time to see things change in Starfish. They do offer an option within Starfish where you can kick off their import process immediately, but I have found that that "immediately" process can take ours to actually run and then complete.
I have found the documentation not be very helpful and poorly written. Especially compared to what we are used to with Canvas and the great job the Documentation team does.
The one thing that seems to be used here is for students to be able to make appointments with an instructor during their office hours. But note while this works great for students there are many gotchas and hoops to jump through to get this setup correctly.
Hope this helps.
Brian