What is الثالث المقرب?

Both give strong access to a character's inner life, but first person uses 'I' and limits you to that narrator's voice entirely. Close third uses 'he/she/they' and keeps sentence-level distance while still conveying the character’s thoughts and sensations, which can be easier to shift into or out of for variety.

Yes—many stories use alternating close third chapters or sections, each anchored to a different character. Be clear when you switch (with chapter breaks or scene markers) to avoid confusing the reader about whose inner life they're in.

Head-hopping happens when the narrative slips into another character's thoughts without a clear scene break. Stay disciplined: in any uninterrupted scene, filter descriptions and internal commentary through the anchored character’s perceptions, and use breaks when you need to move to another point of view.