I’m in a similar scenario myself.
We are trying to avoid duplicating feature files for different tests types, e.g. Manual Test, API, Mobile Browser (Appium) and Desktop Browser (Selenium).
The plan is to create a unified Scenarios held in a central repository.
The write the separate step definition for API, Desktop and Mobile based on the definition in the central repository.
It’s very early days at the moment as we are just writing the feature files at the moment. But I’m aware this could be a very brittle process because if somebody updates existing feature files, it has the potential of breaking API, Desktop and Mobile automation.
If anybody has been there and done this and has the solution I’m all ears 
The last thing I want to do is create separate feature files for each test type.