Can I keep track of one specific app's sales from someone else's iTunes Connect page?

Solution 1:

They are correct, a user on iTunes Connect has access to all apps, no matter what their role. Obviously this is a terrible design, but Apple has never been too quick to fix design flaws in iTunes Connect.

As you mentioned appFigures has the ability to restrict a sub-user's access to individual apps. The publisher will have to set up the primary account.

I can't find official information from any of the other analytics providers that they have this capability. My App Annie account definitely does not.

Solution 2:

Ultimately, no.

iTunes Connect doesn't allow for that kind of split-reporting stuff.

But...

During WWDC 13 a new feature was announced for iTunes Connect: app transferring.

If possible, you could have the app transferred to your personal iTC account. I'm not familiar with your particular situation with contracts, revenue splitting, etc., but this is one way.

Solution 3:

I think that you need to request a financial authority to download the payments report, and then use an App to view the report. There is an App called ReportX can view the details of your App sales and provides tables and charts to sort and compare.

https://itunes.apple.com/app/reportx/id1328409005?mt=12