I don't think you technically have to be that old before you can do most things. 6, I think.
The only things you cannot do at 3 is mate and attack. Besides that you are completely independent, mechanics-wise.
I think there are. At least it seems we have some in the kitten's village, and an expedition is being prepared out of the island. Don't know if it's only RP, though.
Boats were very recently introduced into the game. It looks like Lumin is working back into the game.
