As I understand it, the LCD panel's functionality is built into the factory head unit. So if you remove the head unit, you lose the LCD's functionality. Unless the head unit you buy specifically has those functions built in, like some of the custom, but off-brand units from China.
Pioneer should at least have an adapter available to let you retain your steering wheel controls, though. But that's usually a separate purchase from the head unit itself, as an accessory.
