Gabi
I'm inclined to think that it is the same man, because although he was first a Midshipman in 1794 on HMS London, Lieut Commander James Fegen, he would not be described as an officer until Commissioned, although the description 'seaman' is rather unusual.
I've highlighted his first Captain, because it was common for young men to be appointed Midshipmen on a family members ship, in this case possibly his fathers.
I also wondered if you had checked at the National Archives to see if his Lieut's Passing Papers have survived. If they have, they could contain vital family information.
Martin