As noted on the main page, K.C. Undercover features a visibly different president than the Barack Obama Expy consistently featured in other DCLAU shows. Now, consider that Best Friends Whenever is also part of the DCLAU and has had its protagonists travel through time to the 1950s, 1970s and the early 1990s, not to mention several points in their own pasts. While we don't see anything obvious, who's to say that they didn't do something offscreen that changed who the president is? If it was subtle enough, they might not even realize it themselves.
Every single creature that exists in Wizards of Waverly Place is automatically implied to exist in the hidden depths of every other DCLAU series. All of the near-disasters that have happened in Wizards (Gorog's attempts to take over the wizard world, the asteroid that nearly destroyed Earth - which incidentally actually was acknowledged in one or two of the DCLAU series (possibly)) and for that matter any other show are implied to have happened across the other shows as well.
