The first question indicates that the neighbour did say something. It is about to whom did the neighbour say:
Did the neighbour say something to you? (or to someone else?)
(أم قال لغيرك؟) أَلَكَ قالَ الْجارُ شَيْئًا؟
The three others seem to be similar and do not indicate whether the neighbour said something or not in the first place:
Did the neighbour say something to you? (or he did not say something to you?)
أَلَكَ قالَ الْجارُ شَيْئًا؟ is just like أفي المسجد صليت؟, which you would only ask if you knew for certain that your interlocutor had prayed and were only attempting to ascertain where he had prayed.