Who are the two Istari mentioned in Shadow of Mordor?

Question

One of the artifacts found in Middle-earth: Shadow of Mordor is a Broken Staff, accompanied by this memory:

Funny thing, that. They told us their names, plenty of times. But we all forgot. To a man, we forgot. It was like they didn't want us remembering. After a while, they were just the two Istari, and sometimes, the big one and the little one.

Can't say how I can't remember. I remember the bigger one telling us stories of a Goblin city, of a man who could turn himself into a bear, of the time when… well, I guess it didn't matter too much to him that some of his stories needed some cleaning up, or would scare a dead man out of his grave.

When the bigger one left, he took his cane. But he left a walking stick behind, with all these little notches cut into it. He was keeping track of something, for sure.

Are they the Blue Istari? They could conceivably be Gandalf and Radagast (unless these two were established to be elsewhere). The Shadow of Mordor Wiki suggests these are Blue Istari. Does the canon have anything to say? All I recall from Unfinished Tales is that they went East.

Answer 1

According to Shadow of Mordor, they were killed by the Black Hand.

That means they only could have been the Blue Wizards, which was the most likely explanation given their location anyway.

I think they went as emissaries to distant regions, East and South, far out of Númenórean range: missionaries to enemy-occupied lands, as it were. What success they had I do not know; but I fear that they failed, as Saruman did, though doubtless in different ways; and I suspect they were founders or beginners of secret cults and 'magic' traditions that outlasted the fall of Sauron.

(Unfinished Tales)

Answer 2

These are the remaining two Istari of the five said to exist in The Lord of the Rings and correspond to the Blue Wizards in Tolkien's other writings.

However, Middle-earth: Shadow of Mordor is a game licensed through Middle-earth Enterprises. As such they can only legally pull information from The Hobbit and The Lord of the Rings.

So while they can refer to their having been another two wizards (since The Lord of the Rings says there were five), they cannot say that these wizards were Blue, or to give their names, as doing so would require using material from Unfinished Tales or The Peoples of Middle-earth.

So the total "canon" that the game is able to pull from just says that another two wizards existed (which fits), and their names not being mentioned in the game seems to be designed as a way to avoid contradicting the information found in other books without infringing on copyrighted material.