Does the iPhone version have the same features as the iPad version?

Yes, beginning with version 13.8 which added the Terrain Profile View to the iPhone, all ForeFlight features that are present on the iPad are available on the iPhone.

 

NOTE: the iPhone document annotations currently include Drawing, Squares, and Text. Lines, Circles, Paths, and Notes cannot be added in the iPhone, but can be viewed if they are added to a document using an iPad.