Steering wheel controls can be used with most aftermarket HUs using an adapter, ASWC is one from Axxess. How effective depends on the radio, I have a Pioneer and only vol up/down works.
The aftermarket HUs come with a built-in mic or an external one that plugs in. The plug-in one on my Pioneer works well. The OEM mic has an unusual configuration and I would not attempt to use it with an aftermarket HU - just use the one supplied with the new radio.
The aftermarket HUs come with a built-in mic or an external one that plugs in. The plug-in one on my Pioneer works well. The OEM mic has an unusual configuration and I would not attempt to use it with an aftermarket HU - just use the one supplied with the new radio.