If gnomes built a village, this would be like an underground base, hidden among trees and illusions to avoid raids by gnolls, orcs or hobgoblings.
Halflings and gnomes are perfect as background characters if you would rather a family-friendly style.
I imagine aasimars like victims of tall puppies syndrome, something like the children in the classroom reject the student with the best grades, and interested into other threats. They are gifted, and they should be respected, but they suffer the opposite. Do you remember Lex Luthor's hate against Superman? Something like this. They are the cinderella suffering bullying by the stepsisters. In the eyes of the crowd, they aren't humanoids with a purer karma, but reincarnated celectials who were punished for some sin or crime. William Shakespeare said: "Be thou as chaste as ice, as pure as snow, thou shalt not escape calumny."
Even they suffer a harder pressure to seem as saint as possible. In my land we say "Caesar's wife not only has to be honest but to seem it". Any possible scandal linked with an aasimar is worse. Sins by an aasimar aren't so easy to be forgiben and forgotten. Do you remember the Stark noble house in "Game of Thrones"? Don't hope aasimars to enjoy a better fate, or like saint Joan d'Arc. The fact is even aasimar children are one of the main targets of evil cults for sacrifices. If an evil lord suspect an aasimar children will become a witch-hunter/vampire-slayer, then agents will be sent to make "it seemed an accident".
It wouldn't be rare at all aasimars being tried for false accusations of collateral damage in her last quest, for example. An aasimar could go to a brothel to rescue kidnapped children, but rumors would tell that he went there because he is a sinner who wanted to have fun. If an aasimar can't be defeated in the battlefield, then the main attacks will be against her prestige, telling for example to be a wolf with sheep's clothing, or worse things.