A clue that Grey turns out to be a villain? He's the only shape referred to by his colour rather than by a human name.
It makes sense that Chris would fall in love with Laura, since he's openly jealous of Thomas' jumping ability, and Laura enables him to jump farther.
That Thomas and company aren't the A.I.s to cause the singularity is obvious when they each have an easily definable trait or obsession that encompass their whole personality. Jo and Sam make more sense as the A.I.s to do so because their personality is the most full and human, and the only reason Paul isn't with them is his heroic sacrifice against Grey, who still is based on his primary obsession.
