Tom Cavanagh Will Stick Around
Over the past two seasons of the show, Cavanagh has played two separate characters: in the first season, he was Eobard Thawne, aka Reverse Flash, masquerading in the form of Earth-1's Harrison Wells. In Season 2, he played Earth-2's version of Harrison "Harry" Wells. However, in the Season 2 finale, he and his daughter Jesse returned home to Earth-2 with the help of Earth-3's Jay Garrick.
Thanks to the events of the Season 2 finale, Cavanagh could be playing an entirely different character: the original Earth-1 Harrison Wells. In the finale, Barry upset time as he knew it, which means it's entirely possible that Reverse Flash never went on to murder Wells and his wife.
"I will say that it's enjoyable that by the time this season ends, if I get to play three different characters on the show, I can check that off my bucket list," Cavanagh joked at SDCC.
The Return of Jesse Quick
Like father, like daughter -- sort of. Jesse Wells will also return to "The Flash" for Season 3. While Violett Beane will definitely reprise her role as Jesse, it's unclear in what capacity. As Beane herself said, "[I] could be Earth-1 Jesse, [I] could be a speedster, who knows."
Nevertheless, she remains hopeful that Jesse will become a speedster in her own right: "When Jesse got hit [by the particle accelerator], I was like 'It's happening! It's happening!' There was the spark when she got out of the coma, but... it didn't happen, and I was like, 'No!' I'm very excited and would love for it to happen early next season."