Thought it would make sense to share with the community the information I have discovered to help with configuring O365 federated login accounts and troubleshooting guidance for federated IDs:
Support for Multiple Top Level Domains: http://community.office365.com/en-us/w/sso/support-for-multiple-top-level-domains.aspx
Error when you try to configure a second federated domain in Office 365: “Federation service identifier specified in the AD FS 2.0 server is already in use.” http://support.microsoft.com/kb/2618887
Changes are not synchronized to Office 365 after you update the UPN of an on-premises user account to use a different SSO-enabled domain suffix http://support.microsoft.com/kb/2669550
Troubleshooting dirsync and UPN http://www.ultimate-communications.com/2012/02/troubleshooting-dirsync-and-upn-office-365/
The LsaLookupSids function may return the old user name instead of the new user name if the user name has changed http://support.microsoft.com/kb/946358/