We have an on premise AD and all users have a seperate Office365 account (mix of E1 be E3). Is it possible to migrate the AD to Azure and combine their existing Office accounts so that they have a single set of credentials and can maintain their existing email accounts? We are a not for profit with aging servers so moving to Azure AD makes sense.
You have to remember if you wish to completely remove your on premise AD then you need to think about any GPO's and policies that are being processed via the local AD. Azure Ad Connect is the right tool to sync up to Azure AD. If you wish to do this ensure you look at E3 and Intune in Azure AD to cover of the local features of your current active directory. Just something consider