1) Before the war started, Ukraine was run by a corrupt Russian toady. Russia's in the process of carving off all the regions of Ukraine that voted for said toady, so it's unlikely another would win. Also, it's become clear that conciliation isn't working, so deference to not aggravating the Russians matters a lot less than it used to. That makes them a lot more appealing.

2) Depends on the shield. The GWB-era defence system is land-based, for example.

3) They export both.