1. Yes, you can select a speed all the way down to Vls if you desire, at any stage of flight including approach.
In this video they fly the whole approach in selected speed, and only managed speed from 14:46. If they had been in managed speed from the start, the aircraft would have maintained O/S/F speed as they had flaps 0, 1, 2/3.
Not sure why they did this - it looks like maybe they were given minimum 170kt until 4 or 5 miles by ATC?
2. Yes. Configuration means Flap/Slat setting.