There will be a skill tree, however it is not finished as of yet.
I feel like it's more action packed, but the goal is to make it where you are able to choose how you want to play, whether it's grinding loot, pvp, or pve, you choose how you want to play with risk and reward.
None right now......Not sure how @Joshua feels about this.
It's an idea that we have seen. @Joshua can speak more to this.
Yes there is a cooldown based on what kind of med you use. It applies instantly with a timer for cooldown.
These are being worked on currently. During the alpha you will see some events, but there are many more to come down the road.