Its different for players, not sure why though. Its pitch black for me at night as well, I can hardly see my own character.
To the OP:
Crafted objects like armors, weapons, tools decay by use and eventually break. I have no idea if buildings decay or not, my guess is that they don't.
2 players make a perfect homestead

Homesteads can be fund by 1-5 players.
I believe baskets don't decay now either. I may be wrong though.
Edit: what do you mean by 'safe' ? Safe from other players or safe from decay ? If you put a basket on the ground and you set it to 'private', no one can open it but you. If a player drops a totem beside your basket then he will be able to open it. Everything inside your totem area is safe.