I think it would be great if there was a mod or and update to include Abigail, and when Wendy inspects her in DST she would be like:
''It cant be.. <playername> all this time I thought you were gone"
And instead of having depressing quotes, when Abigail is in a world, all of Wendy's quotes will become cheerful. In DS a way to unlock her would be to have Wendy give a Life Amulet to Abigail to revive her.. Pretty good idea huh? (This makes sense because in DST dead people turn into ghosts and can be ressurected, and Abigail is a Ghost)
And when you revive her, Abigail will be like the Ghost except she will have the same Damage forever, and can die and be ressurected again (IT DOES NOT SOUND LIKE DST ALL YOU HATERS)