Where does Yosemite store cache files for exchange accounts?
You are pretty close for the Notes. If you have an Exchange account set up for Notes then you should have a folder at this location with your Notes.

/Users/USERNAME/Library/Containers/com.apple.Notes/Data/Library/CoreData/ExternalRecords/B059E164-CC3A-44ED-AB92-C703BDD09455/EWSNote/_records/