Forest Chest re-spawns every time you enter the map, but the keys only show up once in each location. One is like you mentioned near the house, another is on top of the Brothel. You also get one as a Quest reward from Saffron and they can rarely drop from chests.
I will check into Juniper Berries, but you should keep them, they are planned as a recipe for brewing Jin and you will need lots per keg.
Yes, some unique items can only be gotten by picking pockets or robbing houses.
You probably increased your Charisma skill. It subtracts the Skill level from the VP/WP needed for actions.
That is not a rock, that was a Frog that jumps in when you get too close, there are three locations like that, two in the Emerald Forest and one near your house. It is just a decoration like birds... for now.
The Caves actually got delayed in favour of expanding the forest as there have been some complaints that there is not enough money to get per day. Thus I decided to expand the "easy" areas first to give players more room to find loot.