Forum:Book of life, cost or effect?

my friend activates Book of Life, i chain Solemn Judgment , my friend thinks he can still remove a monster in my graveyard (namely my Stardust Dragon) , can he , as in iz da part of removin a monster in my graveyard a cost off Book of Life or an effect?

also my friend has a Zombie Master on da field, n uses its effect, i chain Divine Wrath, he thinks he gets 2 keep da card he discarded 4 da effect in his hand as da effect is negated, i say dat it still has 2 b discarded because its a cost. which iz true?

n (dis may seem like a realli stupid question lolz) my friend has a Zombie Master n a Goblin Zombie on da field, im wide open, he directly attacks me w/ goblin n i chain Call of the Haunted n bring bac D.D. Warrior Lady, he recallz his atk w/ goblin n den attacks w/ zombie master , i remove frm play dd n zombie master, he think he can attack again w/ goblin zombie bt my otha friend sez no dat he already declared an attack w/ it dat he cant again, .. i dont kno what happenz here ^^" ..