Hecce:
I'm not too familiar with Folkestone except the docks when using it to take a car across to France before the Channel Tunnel was built in the 1990's.
However - all popular seaside towns in England had/have a similar feel to them - piers, attractions, bathing costumes etc. Edwardian England up to WW1 was the heyday.
The poster for Japan/Russia caught my eye and I did a bit of googling on the rest.
Finkelstein:
As you state - on the Youtube version it notes somewhere that the background noise has been added and that the speed made more realistic (otherwise I guess everyone would be walking at 5 mph!)
So the original - as all films back then were - was silent.