I think you should clarify with your RE. Why wouldn't they just thaw the 2 you are going to transfer? If both didn't survive, then thaw 2 more. If one survived, either thaw one more or transfer just the one. I'd find out how they are stored--individually or are they grouped? No way would I agree to thaw all 5. Not sure if re-freezing is even an option but I'd think that it would be too stressful on them.