Forum:Spirit Dragon and Summoning

So my friend activates level eater/stealer from his graveyard, and I activate my Blue eyes spirit dragon to negate it. Blue eyes spirit dragon can only negate effects from the graveyard once per turn, so my friend then immediately activates that same level stealer AGAIN in the same turn that I just negated it. Can he do this?

Also, in regards to a particular special summoning. All five of my friend's monster card zones were full. He activated a monster in his graveyard whose name I cannot recall. It's ability was that by returning a monster on the field to the hand, he could special summon this monster from the graveyard. Can he declare this special summon even though his monster card zones are full?