Goten and Trunks cannot win.
As per Standard Battle Assumptions, Cell is ultimately going for the kill here.
Cell has knowledge of the Fusion Dance, meaning it is aware of how the technique is performed and its effects. With that knowledge, Cell is most definitely going to make sure that they do not fuse and overpower it. The reason it tried to abuse Gohan and force his hidden potential out was because Goku hyped this power up, and that naturally piqued its interest. With Goten and Trunks, however, Cell is trying to defeat them — nothing like the Cell Games, a tournament it hosted in order to entertain itself.
And, since Gotenks is not happening, the two of them simply cannot win. They are, at best, a fair bit stronger than Gohan when he participated in the Cell Games, but that level of power is still a drop in the water compared to the level of power that Cell possesses, even while suppressed.
They have no wincon because Cell knows they can fuse off-bat and is definitely going to prevent them from doing so.