If I control Kess, Dissident Mage and there is a Force of Will in my graveyard, is it possible for me to cast the FoW for its alternate cost(pitching a blue card from my hand)?
Yes, Kess isn't like other cards that give an alternate casting cost to cast from graveyards(Snapcaster Mage). She simply lets you cast a card from an usual place so you can apply other alternative casting costs to cards cast this way.
If I control Kess, Dissident Mage and there is a Force of Will in my graveyard, is it possible for me to cast the FoW for its alternate cost(pitching a blue card from my hand)?