While a point is made about Cobb's need to reject Mol because she's not real enough, the film also makes the point that Cobb is the one dangerously tripping the line between reality and fantasy. All the other members of the team and comparably grounded; but he has lingering doubts even about the real world (and why not? Mumbasa's events unfold like a fantasy, as Mol astutely observes). This is reflected partly in Mol, who, remember, is an aspect of his subconscious.
As for the kids not looking older? I chalk that up to movie shrug-off.
But why do they behave exactly as they did in the dream? That's just too neat. We don't know whether the top slips or not (and that may not be relevant)* but the children are perfect. I dunno, even without the totem spinning I would have taken that to be a dream automatically on that strength.
Arthur, the sidekick, makes a big point about having your own totem and letting other people know its properties would defeat the purpose... but Cobb's totem is Mol's, not his own. What ever happened to his own totem is unclear - and while specifically how Arthur's loaded dice work is secret, how Mol's totem works is common knowledge in the team (or at least among two members.)
I don't know if that points to anything, but it does shade the totem with the tiniest bit of doubt. Or I could be overthinking it.