Hybrid Server in DR. Doing failover

Hello,
I have a question regarding doing failover for the Hybrid server (Exchange 2010 SP3). We have one 2007 CAS and one 2007 MBX server and one Hybrid server Exchange 2010 SP3 in the main site. Also, the same in the DR site – One 2007 server CAS/HB, One 2007 MBX and One 2010 Hybrid DR. Other then setting up all Web services directories, certificates, what else is needed to make sure that we won’t lose the mail flow. I added DR Hybrid on the Send connectors to O365 and 2007 DR Exchange on the internet Send Connector. Also, I exported O365 Receive connector from Primary Hybrid server and imported it to the DR Hybrid Server.

Please let me know ASAP if I am missing anything else and what else I need to check……
Thank you so much!!

We will be using same name and same external IP for Hybrid DR. So, I setup all URLs for Web Services directories…EWS, Autodiscover, ActiveSync, OWa, etc already.
I imported cert with the same name.

Please also advice if I need to check smth else on the 2007 servers.