Alien: The Weyland-Yutani Report, az in-universe written book. While I don't own a copy, but I am aware of what is written in it. I have to say, that if we use it as a canon soure, then it s pretty much render non canon nearly all Expanded Universe source material. First of: the thing with the United Systems. In the book, its written, that this goverment created in 2202, and the millitary arm in 2226. The problem is, that they are nowhere to be found in the EU (both in the old, or the new comics/books). Also, we know that the Interstellar Commerce Commision is the ruling goverment, they are alive and kicking in the 2250's as well. Let's just assume that it's a slip of the pen and the United Systems created in 2302, not in 2202.
Also, the W-Y Report states, that the Weyland-Yutani born in 2099 via the emerge of the Yutani and Weyland Corp. What's the problem with that? Well, the W-Y already existed BEFORE that! AvP: Sand Trap, set in 2007, the first appearence of the W-Y logo. Aliens: Steel Egg: the W-Y existed in the 2040's. Given that in the game, Predator: Concrete Jungle (set in 2030) there we see the Weyland Industries (and not Weyland Corp, theay are two separate company) and the Yutani Corp two separate thing, So the W-Y must be created between 2030 and the 2040's (but the two company worked together a while in secret, as seen in Sand Trap, but only united officially after 2030). Either way, the Weyland-Yutani couldn't be created in 2099, because its already existed. My theory is very simple: the W-Y fall apart, or just renamed itself Yutani Corp again, in that way, the Yutani and Weyland Corp could emerge as a new Weyland-Yutani. In this way both the Alien: Weyland-Yutani Report and the EU material could be canon without contradicting each other.
