Jade it's a completely unreliable Twitterer in that she only reveals exactly what she wants people to know or that they already know. Pictures of her with Chef Hottie on Christmas Eve came out the day before she posted on her own, and she posted that pic acknowledging she was at the beach after someone had posted a pic and just before or right after she left. However, any time she's with other HMs, aside from Ed alone, she's been pretty open about her activities. I can't believe that if she's still hanging with Tim she'd be hiding it and Tim's certainly not shy about that kind of thing, so I can't imagine him pretending to Twitter her about the shark thing when he's right there with her.
Tim and Jade have many common interests and Jade gets Tim and accepts him for who he is. I think they will always have a close bond but Jade doesn't trust easily and once she's been burned, she doesn't seem to give many second chances with that trust. Tim has publicly spoken about the Jade/Ed relationship and Jade was not happy. I don't see her giving him any ammunition, just because she knows he has no filter at times.
As for any lingering Ed issues, this is Jade. Her biggest flaw is that she loves way too much. She's going to have feelings for Ed for a long time, feelings that no doubt will give her some turmoil if she ends up in Melbourne for the Open. But the fact that it is in Melbourne, where Ed is in his glory and at his worst, means that, more than likely, the same barriers to their relationship will still be firmly in place. Even if for some reason he reverts back to some type of courting behavior (unlikely but Ed has zigged instead of zagged before) he's still in the environment where he's more comfortable with his mates than a woman and the douchiness will prevail. It always does. If anything, the trip could be a necessary reminder of that fact. Distance, fond memories, and loneliness sometimes make the "what if"s and "if only"s more intense and a dose of reality can be necessary to counteract the romanticized reflections.