When the characters leave play at the end of turn is it all at once or one by one so Say I have a deckbox.org/whi/Dwarf%20Ranger can i say he goes into the discard pile last so I can trigger his effect for all the characters going into the discard pile from Reclaim?

Another question that has come up about the Ranger when he does damage to the capital who gets to assign what parts of the capital takes the damage?

When a group of units leaves play due to the same effect (Troll Vomit, Judgment of Verena, because they were reclaimed, etc.), they leave play simultaneously. So no. The Ranger himself is gone by the time his effect could kick in.

The player controlling the Dwarf Ranger gets to pick which zone the damage is dealt to. It is his effect after all.