I wouldn't be shocked to see James Franco and Freida Pinto simply not show up in any sequel to Rise; they were, hands-down, the worst parts of the movie. Fox wisely understands who was the heart of the film, and now he's all set up to come back and play Caesar again.
But what about an Oscar campaign? The details of Serkis' deal are unknown, beyond the fact that he's getting a whopping (and well-deserved) seven figures. Is it possible that his agent built in a deal for an awards run as well? Now would be the time for Fox to get started on it, and since Serkis is the key element of their newest franchise, it would be worth making him happy.
At this point an Oscar campaign seems semi reasonable. Not only is Serkis' work in Rise phenomenal, this is his third go-round in an 'awards worthy' mocap role. After Lord of the Rings and King Kong it's possible that Academy voters are finally ready to start treating performance capture as actual performance.