Community manager Acheval posted two clarifications about the upcoming Tribes of the East expansion on the official forum. The first one is about the stand-alone nature of the product and the inclusion of some Hammers of Fate content:

"As mentioned in the announcement, ToE will be a stand-alone product. It will work by itself, as an add-on for Heroes V, or as an add-on to Heroes V and HoF. As a stand-alone, it will include all factions (including the dwarves) from the previous titles, but not any of the other content (maps and campaigns)."

The second one is about the alternative upgrade levels, but you probably figured out what they did by yourself already. On a completely unrelated note, we still haven't found a good nickname for the expansion. What will be the follow-up to Farmers of Hate? The best I can think of is Brides of the Beast, but what do you suggest?