Can the amp plugs be moved further up the wire and the wire be shortened?
No, the amp pugs are installed at the factory with special tools, which would be required to move the plug. Any excess wire can be simply coiled up and set aside in a inconspicuous place on the top or back of the cabinet. It is not recommended to cut the plug off and wire lights to power sources. Low voltage requires solid connections to prevent “arcing” and with design of amp plugs and pins this prevents this.