Wise Wizard Games Hero Realms Wwg500 The Card Game

We too often have six-players. Can 1 core set + 2 hero character packs work for six players or do I need 2 core?

Do I need two of these core decks to play with 4players, like in star realms? Do I need 2-sets of character decks to play 4-players too?

Does this include the class decks?

How many cards fit in the core game box? Is there room for character decks?