Arrangements

Your grid is right, and so are the answers that follow from it.

Answers

• Q1 — (b) B2
• Q2 — (d) None of these
• Q3 — (c) G1 and B6

Your arrangement

Row 1:   B5     B3     B2     B4     B1     B6
Row 2:   G1     G6     G4     G5     G2     G3

Clue by clue:

• (I) B5 is at an extreme end and immediately right of B3 ✓
• (II) Of G3 and G4, exactly one (G3) is at an end ✓; G5 sits exactly midway between G3 and G6 ✓
• (III) B1 is left of B4, faces G2, and is not at either end ✓
• (IV) G6 is immediately left of G4; B2 is immediately right of B4; G6 does not face B2 ✓
• (V) B6 is left of B2 ✓

Working the three questions

• Q1 — B2 sits immediately to B3's left. Option (b).
• Q2 — the facing pairs are G1–B5, G6–B3, G4–B2, G5–B4, G2–B1, G3–B6. None of G4–B6, G2–B3 or G1–B1 appears, so option (d).
• Q3 — the four end seats are B5 and B6 in row 1, G1 and G3 in row 2. Only option (c), G1 with B6, names two of them.

One thing worth knowing

In face-to-face row puzzles, "left" and "right" flip between the two rows — the boys' left is the girls' right. Read that way, the girls' row reverses to G4 G6 G5 G3 G2 G1. Different picture, but check it: B2 is still immediately left of B3, no listed pair still faces each other, and G1 and B6 are still both at ends. All three answers hold either way, so nothing here turns on the convention. On a set where it does turn on it, fix the direction from a clue that mentions both rows before you place anyone.

Sorry this took so long to come back to you.