The above given suggestion looks good to resolve your concern and accomplish the task without any trouble.
However, I would suggest you to checkout Exchange server deployment assistant that could also be a nice approach to deal in such situation : technet.microsoft.com/.../dn756393.aspx
Moreover, if you wish you may also look into LepideMigrator for Exchange(www.lepide.com/exchangemigrator ) that could be a good alternative solution to get this job done flawlessly without any downtime.