Case file LinkedIn Crossclimb #872: 4-letter ladder, 5 middle exhibits, combo prompt "A compound word for a rescue item on a ship.". Endpoints: LIFE (top) and BUOY (bottom).
Middle phase answers: "Another word for what's called an elevator in North America" = LIFT; "You might make one for a shopping trip" = LIST; "One of the seven deadly sins" = LUST; "Sculpture of the upper part of the body" = BUST; "Having lots of things going on" = BUSY.
Ordering phase: the valid middle chain is LIFT → LIST → LUST → BUST → BUSY. This permutation is the only valid one-letter chain for these answers.
Evidence link: LIFE → LIFT. E→T at the fourth letter (LIFE → LIFT).
Evidence link: LIFT → LIST. F→S at the third letter (LIFT → LIST).
Evidence link: LIST → LUST. I→U at the second letter (LIST → LUST).
Evidence link: LUST → BUST. L→B at the first letter (LUST → BUST).
Evidence link: BUST → BUSY. T→Y at the fourth letter (BUST → BUSY).
Evidence link: BUSY → BUOY. S→O at the third letter (BUSY → BUOY).
Verdict: LIFE → LIFT → LIST → LUST → BUST → BUSY → BUOY satisfies every one-letter constraint. The combo clue "A compound word for a rescue item on a ship." describes both end words together — "LIFE" and "BUOY" each differ by one letter from their adjacent middle rungs and satisfy the shared top+bottom prompt.