Azure AD authentication capabilities

Hi,

I have a hybrid environment with on-premisses Exchange 2010 and Office 365 working great with DirSync and ADFS 2.0 doing SSO.
Now i will move all users to Office 365 and uninstall Exchange 2010, but i'm worried about business continuity in case my links (not reliable) go down and users cannot access e-mail because ADFS is not available
Innitially i was thinking in install a server in Azure with ADDS and ADFS, but i read about Azure Active Directory and don't know if it can do what i need, that is, use Azure AD to authenticate my O365 users without use on-premisses ADFS

Or the only way is to create an AD + ADFS in Azure for users login using their domain account?

Thanks