Gmail for Exchange or Microsoft Exchange Active Sync

We are using Office365 Exchange cloud email accounts. I have configured Samsung Galaxy A3 and there are 2 email apps by default - GMail and E-mail (probably from Samsung?). I have added Google account and Exchange account to the phone settings but then could not find the e-mail account in the E-mail app and found it in Gmail app. On the other hand the Gmail account shows only in the E-mail app. When trying to connect the E-mail app to Office365 account, it creates second Microsoft Exchange Active Sync account that presumably synchronizes independently from GMail Exchange account. It is quite a messy, what would be the most convenient way for the user to configure those accounts and clients presuming that the user wants to save contacts to Google account and view e-mail & calendar on Office365 account?