Everyone has their own opinions, and I 100% respect that. But I honestly think that Dexiana has a very high chance. In my opinion, Dex and Biana have had many more moments than Tam and Biana. A reason why I think so is that in the Dex and Biana page it mentions that Shannon Messenger was going to put in a line, but deleted it. The line was "'Agreed! Biana shouted. 'Or you'll have to face the wrath of the Dizznacker!" This line was cut from Lodestar and I infer it to mean that Shannon Messenger herself, thinks Dexiana is going to happen, but she didn't want to make it too obvious
That is my reason for why I think Dexiana is going to happen. Thank you for taking the time to read my comment.