I consider the Mordirith storyline as part of my own personal headcanon because it's actually a good story that ties up a (possible) loose end of what exactly happened to Eärnur, but most of the rest of the stories in LOTRO directly contradict the books (Moria, Lothlorien/Mirkwood, Great River, Lonely Mountain, Helm's Deep, Grey Company) so I do not consider them canon in the slightest.
[I]In the sea without lees standeth the Bird of Hermes.
[/I][I]When all his feathers be from him gone, He standeth still here as a stone.
Here is now both white and red, And all so the stone to quicken the dead[/I][I].
The Bird of Hermes is my name, Eating my wings to make me tame.[/I]