Case 1: Imam and follower both offer the same Zuhr fard — generally valid if other conditions are satisfied.
Case 2: Imam offers nafl and follower fard — not valid in the cited Hanafi ruling.
Case 3: Imam offers Asr fard and follower Zuhr fard — not valid due to differing specified obligations.
Case 4: Imam offers fard and follower nafl — permitted in the cited Hanafi ruling.