Absolem idea
I admit, I have yet to see ATtLG yet (it isn't available in my area, at present) so this 'spit-balling' is based solely on the first movie and what I've read about the new one.
In light of the sad loss of Alan Rickman (R.I.P. to a wonderful actor and even better human being), I had read a lot of fans talking about what would come of a third ALICE movie and the character Absolem. One thought a friend and I had, was that they could hire someone who could make their voice sound similar enough and then have them be the brother or son of Absolem. That way there would be a way to give his character a proper goodbye from the characters (and fans) but without having someone else take on the role and do an impression of Alan Rickman.
"There is still hope." - Arwen