Proxmox upgrade from 2.2

Hello,

we have two proxmox servers in our office. Not clustered.

One is running version pve-manager/2.2/3089a616The other is running version pve-manager/2.3/7946f1f1

I'm planning an upgrade of both servers individually. My first one will be the 2.2 version. Then I'll upgrade the 2.3 version.

Question #1:
Can I upgrade from 2.2 directly to 3? Or do I upgrade to 2.3 first? Where can I find the steps to upgrade my 2.2 server?

Question #2:
I've read the wiki to upgrade from 2.3 to 3: http://pve.proxmox.com/wiki/Upgrade_from_2.3_to_3.0
In the troubleshooting section I see a reference to removing 'fuse-utils' package. Does this need to be done for every host running proxmox 2.3? Or just for some Hosts (where I will discover the problem when I reboot)?

Question #3:
Question for both servers. Do I need to use apt-get update && apt-get upgrade at all during my task to upgrade my proxmox servers? When do I need to update and upgrade my proxmox servers (if at all)? Regularly or never?

Thank you.