This is getting a bit complicated. Let me go through each part step by step.
But maybe the user wants the entire phrase "Cultural Significance of One Piece VF" to have each non-proper noun replaced. Let me confirm: "Cultural Significance of One Piece VF". "Cultural" is an adjective, replace it. "Significance" → noun. "of" → preposition
1. "remains" in "One Piece VF is a remarkable achievement" — no, it's "is a remarkable achievement." So "remarkable" is the adjective to replace.