>>96397164With the whole Ghost powers thing she's going to be essentially a new character, and to be perfectly honest its not like Alice was anything sacred in the first place. She's there so there can be someone other than Hellboy to receive exposition and eventually be something more for Hellboy to be sad about.
And Mignola's always been hands of with adaptations. He created Joe Golem specifically as a back up in case the first film was so bad it sunk the character.