If there's going to be 15 songs on The Lost Children, it shouldn't be too hard to guess which will make the cut.
Loading the Weapon: Unrecorded
Dehumanized: Stricken Single, CD 2
Ten Thousand Fists Era
Monster: UK Tour Edition, Ten Thousand Fists (iTunes Bonus Track),
Hell: Stricken Single, CD 1/UK Tour Edition
Two Worlds: UK Tour Edition
Sickened: UK Tour Edition
Run: Indestructible Limited Edition
Parasite: Inside the Fire single (iTunes edition)
Leave It Alone: Asylum Special Edition
Old Friend: Unreleased (leaked on Internet)
Emptiness: May not exist/never finished
Glass Shatters: WWF Forcible Entry
Liberate (Matrix Remix): The Matrix Reloaded: The Album
Stupify (Fu's Forbidden Little Nicky Remix): Little Nicky soundtrack
Forsaken: Queen of the Damned soundtrack
Midlife Crisis: Covered: A Revolution in Sound, demo leaked on internet
Living After Midnight: A Tribute to British Steel, Another Way to Die single
3: Free The West Memphis Three Charity on D1.com
Any guesses? We can rule out 3 since they don't plan to profit off that song, Forsaken because David has consistently said that it's Jonathan Davis's song and not his, Emptiness because it probably doesn't exist, Loading the Weapon because as far as I know it's never been release in a studio-form anywhere and Little Nicky Stupify and Matrix Liberate because they're just remixes. That leaves 13 songs. Glass Shatters is a bit iffy since it's technically a cover/re-imagining of Jim Johnston's theme of Stone Cold (they might let it slide since it's both a rarity and they seem to be allowing covers).
David has been mum regarding God of the Mind and A Welcome Burden, despite otherwise confirming other questions related to the song-list. I'm guessing the 2010 version of The Sickness will be replacing the original, meaning those two songs have probably been completely canonized into the Disturbed discography.