1) The new staging steps rules, where each player individually flips one encounter card during the staging step. Is this just a way to determine targets for the "you effect" or is there a player action phase for each player after the flip of each card?

2) Is there a easy mode for the Black Riders? It is not listed in the manual and there is no one in the Easy Mode PDF.

1) There is no new player action window. As you surmised, the new rules are to determine who needs to respond when the card says "you".

2) The Black Riders supports easy mode - see page nine of the insert (the cards to remove are the ones with a gold border)