If they meet tsunade alive just in time and they let her die, what use is karin showing up with oro. Oro also has special medical skills and his arms are back. Oro and karin should be able to save tsunade without reanimating her. Abt edo-jiraiya, it's possible oro can bring him back...and they will all return to the battle field. That means more opponents will arise (the alliance is now too much for madara, juubi may revive and reach the final stage somehow) so that all the strong guys can get busy too.