Same goes for Samantha Barks really.
In her case I don't think it has helped that both Fantine and Eponine are supporting roles, so that the attention was always going to be drawn to one instead of both. If one of the roles, Fantine's, had been made more of a leading role, then I think Samantha Barks would have got more attention and possibly more awards.
As for Eddie Redmayne I'm not sure why he's been ignored, like Hugh Jackman there was some flaws in his performance but again I put that down to direction, overall he was great. It's not like he hasn't been recognized in the US before, he won a Tony award a few years ago for Red.
As someone has said you have to have the right people behind you as well as a good performance to make an impact in awards season.