If anyone is still encountering problems with Exchange integration with Gmail 5.0 on the Note 4, I was able to resolve my issues by using an older version of the Exchange Services patch on APKMirror.
I have Gmail 5.0.1 on my Note 4 but using the latest version of the APK (1642443 as of Dec. 15, 2014) would make Gmail 5.0.1 offer up the "Exchange" option when setting up a new address.
After much trial and error, I tried using the older version of the APK, which says it's designed for 5.0 and not 5.0.1 (Version 6.5-1533254), which was the latest fix when I configured Gmail 5.0 on my former LG G3, and lo and behold: fixed my issue with 5.0.1 on my new Note 4!
I was able to integrate my Office 365 work email with Gmail 5.0.1, same as on the old G3!
Hope this can help anyone with similar issues!