The Cuban Missile Crisis was brought to an end through a clandestine guarantee from RFK to the soviet ambassador that US missiles in Turkey would be removed within 6 months of the crisis (they were.) I don't see how a guarantee for prisoner release, contingent upon continued de-escalation of the conflict could do harm to any of the parties involved. Indeed any cease fire agreed to by both sides would be a step forward -- an implicite recognition of the state of israel by hamas as well as an implicite recognition of the legitimacy of a democratically elected government by israel.
Netherlands grants Lebanon $92,3 million to cope with Syrian refugees (AP)
from the article: Gaza groups ready to deal on cease-fire, release of Shalit