If they both win their next fight TJ vs Faber for the belt would be not only be likely but almost guaranteed I think.
If they both lose their next I could easily see them fighting, usually two fighters coming off loses face each other plus UFC would want to cash in on their rivalry.
However, most likely TJ will win and Faber will lose so Cruz. So if that happens I doubt they would fight, but who knows.
Even if they were to fight I think the prefight trash talk would be kinda lame. Both parties seemed to have moved on and TJ is just boring as hell to be honest. Cruz is actually intelligent and articulate, so I think cruz/Faber will have much better out of ring content.