So, as I recall, they say is some moment that dozens or hundreds of thousands of people were captured and are in sleep onboard of the motherships to become food for the lizards... The ending came and the ships left, but I don't remember they saving all those people... What happened to the people in the ships??
In the weekly series that followed, Diana's mothership was captured by the humans so at least all of those people would have been freed. The other ships were hidden behind the moon, though it isn't made clear if the human "cargo" was freed from them or not.
Since at the very end of the weekly series the Visitors' leader agrees to a truce with Earth, the human cargo on the other ships was most likely freed. It just would have happened offscreen.
Well, at least most of them... Or the visitors weren't feeding on humans yet? . They could feed on animals, since they outnumber humans and you use more meat from big mammals as cows for example... What was the excuse for the visitors need to store humans as food source??
The Visitors came to Earth because there was a shortage of water and food on their homeworld. But instead of just killing humanity so they could steal the water, why not harvest them as food (since the Visitors are carnivorious). They were storing humans to take back home the way we might put a chicken in the freezer (though their food has to be kept alive). We don't actually see them eat any people in either of the miniseries, but in the weekly series there's an episode where the Visitors unveil a new "food processor" which humans are put into so they can be eaten. I can't remember exactly what it did, but you heard a man scream when he was put into it.