The Future Perfect Continuous tense is rare but specific in its usage. Analyze the statements regarding the nuances of this tense:

I.The Future Perfect Continuous (e.g., "By next year, I will have been working here for ten years") emphasizes the duration of an activity that will be in progress before a specific reference time in the future.
II.Unlike the Future Perfect Simple ("will have worked"), which focuses on the completion of the action, the Continuous form draws attention to the ongoing nature and length of the event up to that future point.
III.Stative verbs (like 'know', 'believe', 'own') are frequently used in the Future Perfect Continuous to emphasize the long duration of the state, as in "I will have been knowing him for years".

Is it correct what is stated