Ok,
I see that the engine is trying to deploy the second host as an hosted-engine one but the engine sends only HOSTED_ENGINE_CONFIG/host_id=str:'2'
while all the other values are missing.
2017-05-25 02:40:31 DEBUG otopi.context context.dumpEnvironment:770 ENV HOSTED_ENGINE/action=str:'deploy'
2017-05-25 02:40:31 DEBUG otopi.context context.dumpEnvironment:770 ENV HOSTED_ENGINE_CONFIG/host_id=str:'2'
Could you please check your engine logs for 'ERROR [org.ovirt.engine.core.bll.hostedengine.HostedEngineConfigFetcher]'?