Yes, 2) Yes. 3) The correct techincal spelling is do-hicky. The name of the plug is RJ-45. But most people probably call it a ethernet connector/plug. It looks like the connector where a phone plugs into the wall, but wider.
wang3 lu4 xian4 - 網路線 - network cable
wang3 lu4 ka3 - 網路卡 - network card (not sure how to say the actual socket, but that would get you near enough)
wang3 lu4 xian4 tou2 - 網路線頭 - network cable plug
wu2 xian4 wang3 lu4 - 無線網路 - wireless network
Those are what I hear/use in the office but to be honest it’s more common for the English terms to be used.