Hi, Danif
Answer1: The benefit his dual speed MAC is that it can support two ethernet speed(10M/100M). Although 10M ethernet is too old. But there might someplace need such a speed.
Answer2: If a controller has not MAC, I think it cannot be used into a ethernet application.
Answer3: You can find some application example in MQX4.0. After install, you can find some ethernet application in folder: ...\Freescale\Freescale_MQX_4_0\demo.
Hope my reply can help you.
Best Regards
Paul