I've been setting the various criteria since the international policy statement of the Martin government in 2005. That government and several other iterations started with the top criterion being where aid is needed. The second one was where it can be used the best, the most effectively. Often those first two contradict each other, because the poorest countries often have the least capacity, and those that have a great capacity to use aid need it least. For instance, China would have a great capacity to use aid to reduce poverty, but it is not a country in great need.
Often, there has been a third criterion that muddies the water even further. For the Martin government, it was an opaque World Bank score on institutions. For the last iteration under the Harper government, it was alignment with Canadian foreign policy, which I've already spoken against.
My fundamental reading of this is that these criteria could allow you to include any country that you wanted to include. They provide absolutely no guidance. They can give you some cover to say that it aligns with this one or that one, but the criteria are vague enough that you can use whatever political preference you have, and very often these are very political preferences, no matter how much people might say otherwise.
I talked to the people at CIDA after the international policy statement and that new list of 25 countries and asked if it wasn't going to be just a Liberal initiative, such that when the next government would come in, it would change that list. They said no, no, that it was not partisan at all, that they had consulted widely, that these were the 25 countries, and that everybody agreed on them. Then, four years later, the countries were changed again by a different government.