Smyth says she was "daughter of Sir Richard Deverox lord Ferrars", but the only Richard Devereux was not a baron as he dvp, though indeed his father and his son were lord Ferrars.  I suspect Smyth got the title wrong and the connection right; hopefully.

Assuming the father is right, It is possible that her mother was not Dorothy Hastings as Dorothy as mother would make Katherine a very young (and rather insignificant) bride for John Berkeley.  (I wonder if Katherine was legitimate?)