Yes, there had been quite a few cases, but not enough to convince people world wide of their existance. Meeting a human for Simius it's always a potential danger, and there's a reason for why there's so many horror stories about humans. There were, however, positive interactions and even relationships. People who willingly accepted human company would surely he shamed and avoided, so Simius who were in these situations hardly ever let it known.
They were certainly present in the cryptid community and folklore all over the world. They were as belivable as bigfoot and fairies back then, so scientists never entertained their existance.
As before the res cas, yes. Trade was very limited to small territories and families, since moving any further would be dangerous and way too taxing without a bird to fly. In general, Simius pre war were more fragmented.
Post war, trade on longer distances is much more popular, and there are plenty of people whose whole job Is to hop from settlement to settlement to trade supplies. Large communities will even have specilized scouts who will just go to other communities for trading and discuss supplies situation.
It's more common with larger groups, and single families or individuals are not quite as present in the scene. Usually to be a trader you either live next to other people or you must have a bird.
For the city, trade is pretty much relegated to inside of It, with barely any outsiders coming in. They're a dangerous, risky place. Because of this lot of very useful instruments like weaponry or gas masks are not present. Despite this, trading does happen in between people who made home in the various crannies of the cities, always outside of civilian quarters like in sewers.
Simius have plenty of traditions, though they can vary a lot depending from person to person and from community to community, and it especially depends by the people's settings. For example, people who live indoors and people who live outdoors have slightly different ways to train their kids for survival. Some traditions are pretty common all around, and post war there's more multiculturalism in settlements. Funerary traditions are also pretty similiar all around.
The closest i can imagine as "human-like" tradition is that lots of Simius traditions also revolve around eating together, i suppose. Eating is an extremely important thing for Simius, even more so because how much harder it is for them to acquire. An example would be the scavenger initiation, where the meal will be all prepared with things the young Simius brought home from their first supply run.
As for spiritual beliefs, again they're also very fragmented, but not very popular at all. Generally, religious beliefs are about the existence of a greater deity that would simply be nature, rather than a possible god.
