Karai is Splinters daughter Miwa- I think everyone predicts this, they have it set up for this to happen, I kind of hope this doesn’t it though. This plot twist is way overdone and it might be kind of weird for Leo to have a crush on his “sister’. If Miwa is still alive I hope she’s somebody else, not Karai.
Love triangle between Donnie, April and Casey Jones- it is rumored that Casey will appear in season 2 and he was Aprils love interest in other incarnations so it makes sense.
Baxter Stockman will mutate-everyone else is mutating in the series and I think Stockman was a weird fly mutant thing in other versions.
The boy that raised Leatherhead was Casey Jones-not really a serious prediction, just thought that’d be funny.