You can do the retrofit and flash C1A afterward. CIC patcher can activate the following FSC codes.
0017 - Voice control
0019 - Navigation system Professional
001B - Navigation system Professional
00XX - LifeTime Map Code
006F – Satellite Tuner
009C - BMW Apps
Front buttons usually come with the CIC. But I don't know much about small screen versions so check out all the pictures you can find on ebay. And add a combox plug set to your shopping list. You will remove the pins from your TCU and or MULF and insert them into the new combox plug.
https://www.ecstuning.com/b-genuine-...p/61136913644/
https://www.ecstuning.com/b-genuine-...h/61136913626/
As an alternative to the combox, if you have usb in the armrest, you can simply use a tune2air. It will get you bluetooth music with steering wheel controls.
https://www.amazon.com/Bovee-WMA3000.../dp/B0131P6P5E