I noticed quite a few things from the games that were first in th manga. Some examples:
-In one chapter, Arbok is shown to cure status by changing the patten on its body. In Generation 3, it got Shed Skin as an ability. Arbok also had the ability to raise its stats the same way, if I rcall correctly. Doesn't that sound a lot like its DW ability (Moxie)...?
-There's a scene where Professor Oak's Kangaskhan beats one of Agatha's Ghost type Pokemon (a Gengar, iirc) with Dizzy Punch. This may have seemed out of the ordinary at the time, but then in the DP games, it got the ability Scrappy.
There are probably a few more examples I can't think of at the moment. What do you think?