It was bugging me for a bit that the one person who could come up with FTL travel, and the two people who could come up with a drug to stop the descolada, and the one person who could make the recolada all happened to live on the same Portuguese-speaking planet and then it hit me: they are possibly descendants of Bean and Petra (the five kids who didn't have Anton's Key turned) or Peter and Petra's five kids after she remarried. After all, Petra is implied to live out her life in Brazil, so it wouldn't be a surprise for their descendants to be super smart.
The problem with the Piggies killing the humans and trying to get them to turn into trees, and how that's a problem for the humans, makes more sense when you realize that this is the second time that an alien race has tried to judge how human biology works based on how their own does. The Formacs were the first, as they killed the humans under the assumption that individual humans were a hive mind and thus didn't matter.
The exchange between Miro and Leaf-eater near the beginning of the story confused me at first. Leaf-eater asks Miro to say something in Portuguese and Miro tells him "Go eat leaves," a pun on his name. Leaf-eater finds that offensive. If he thought the name was offensive, why did he give it to himself? On re-reading it makes more sense. The piggies picked their names in Stark, a language that they are unfamiliar with. Leaf-eater wants to enter the third life as a tree, trees produce their own food through their leaves. He named himself based on his life goal: Leaf-eater ie: someone who eats with his leaves, not realizing how it would sound to someone who speaks the language fluently. When Miro told him to go eat leaves, it sounded to Leaf-eater like he took a noble and beautiful name and turned it into a joke about cannibalism.
