I will give this a shot and please correct me if I a wrong.
Magic Morning-comes with a three day park hopper and applies specific days of the week. I think it is Tuesday, Thursday and Sunday. This gets you into Disneyland one hour prior to regular admission hours on those select days. Not sure if it has been also applied to DCA.
Early Entry-applies to those staying at one of the three on property hotels. It alternates between Disneyland and DCA every day of the week. You get in one hour early from regular admission hours. Again, on property hotel guests only and you must have your room key.
Extra Magic Hours - I believe is a Florida thing only with a few special day exceptions in CA. Those are where on property guests can stay after the park closes for a few hours.
In a nutshell:
- EMH (Extra Magic Hours) is exclusive to guests staying at a Disney-owned hotel. It offers admission to the parks one hour ahead of regular park opening. Disneyland days are Tuesday, Thursday, and Saturday. California Adventure park days are Monday, Wednesday, Friday, and Sunday.
- MM (Magic Mornings) are for guests with a three-day or longer pass. It is the same extra hour, but only offered at Disneyland park on the above mentioned days.
- EE (Early Entry) no longer exists in name. It's the same as Magic Mornings.