This is the kind of scenario where I'd use a mix of automated and manual testing - manual testing using the iPad, because one thing GUI automation always does is simulate the human inputs. I've found that simulation often has crucial differences from actual input.
For automation, the crucial question here is where the data sent from the ios app is stored. If you're using a database - or any other kind of external data store - you don't need to do unified testing if these circumstances apply:
- You're starting your web and ios tests with a known database state,
- You're checking the data in your database after the test (or tests) are complete.
With database validation as part of your tests, you know that the Frank tests have successfully sent data, and you can then use a database with that data as the baseline for your web application tests.
This is the method I use to deal with testing across multiple applications regardless of what they're running on or what automation framework I'm using.
If your applications don't use a database or external data store but rely on live communication things get much more complex - I wouldn't try to offer suggestions on that without more information about how your application architecture is configured.