As the article stated, these are only predictions, so this particular prediction may not be based on any inside information at all. In fact, they mentioned that they only got 30% of their predictions correct for last Season. So for the time being, I’m treating it as just a prediction, and nothing concrete. This isn’t one of their Blind Item articles.
In the event that somebody is written off, though, it’s hard to say for sure. Rumple seems like the safest bet, but permanently writing him off the show has been a common theory since Season 4, so I still think it could go either way. There was a rumor awhile back that Bobby was only willing to do one more Season, but who knows how true that is. I also don’t see it being Zelena for the reasons stated above. Not to mention that Zelena now has a baby, and she is the baby’s only living parent as a result of Robin’s death. I guess if they wanted to they could kill Zelena off, and have Regina raise the baby. I’m not sure how I’d feel about that, though.