MongoDB deployment across cloud and On Premises

We are planning to implement MongoDB as a stretch cluster which includes Primary secondary in DC 1, Secondary secondary in DC 2, Arbiter in cloud(DC 3) where DC 1 and DC 2 are on premise servers and DC 3 in cloud My questions are : 1) Should we need to keep same OS in AWS as our On-premise server or we can keep Amazon Linux also ? In our case it is RHEL 7.2 in On premise servers 2) If No, will there be a performance impact if we use different OS between replica nodes ? 3) If yes, Do we need to do patch upgrades as frequent as we do in On Prem servers ? 4) How the failover works here in case of write concern as Majority ? 5) What are the other trade-offs in this approach if any ?