Findings 1 for iOS is compatible with Findings 2 for Mac, just like it is also compatible with Findings 1 for Mac. There are a few limitations related to the new features, of course. All entry types will appear as experiments in Findings 1. Standalone timers, collections and entry status will not be visible in the older version.
We plan to release Findings 2 for iOS later, and first focus on the Findings 2 for Mac release.
Let me know if you have more questions!