Clearly they should feud, am I right?
WrestleMania would make sense but I really don't think that there is any room on the card. Seeing as names like Lesnar, Bryan, Rollins, Cena, Ziggler, Ambrose, Rusev, Wyatt, Reigns, Triple H, Sting and The Undertaker will all most likely work the card, I don't see how Rowan and Harper will fit in.
Perhaps at the PPV in between the Rumble and Mania, but why begin a big feud like that when theres no room on the biggest card of the year which is the following event. To be honest, I don't see them entering any big feuds until after Mania passes.