hunger is depleted whenever you do an action like woodcutting or mining.
Just to clarify: The yellow bar that shows hunger will reduce over time as well, just like you'd expect someone in real life to get hungry even if they do nothing. However: crafting, gathering materials, fighting, all of it will make your character go hungry faster. A hungry character will regenerate health (red bar) slower when wounded, so it's vital for your character to carry food with them when out adventuring. An empty hunger bar will also cause your character to starve to death, if not fed in time.
As to number 3, let me elaborate on that one as well:
It is as easy as leaving your town to become an outlaw. However I can't recommend it for a new player, as you will probably lose your motivation rather quickly due to reasons below.
An outlaw won't pay taxes, and won't be bound to the laws and leadership of the three realms. That's the good thing they got going for them.
However an outlaw also won't receive magical gems from taxes, obtained every 8th day (IG month/tax day) after you raise your rank at least once.
An outlaw also won't have access to static tools to do crafts, unless the town allows outlaws to access them.
There are a lot of useful quests, especially to new characters, that even grant a lot of free stuff, in each town. An outlaw misses out on that.
Characters are often more friendly to people of the same town, while a few discriminate against outlaws since most of them are criminals.
A criminal is very difficult to roleplay well without ending up being shut out from others roleplay (EG: Some criminals are attacked on sight and chased away. It will be hard to find constant roleplay then, and most of those who play such criminals have multiple characters to make up for that so that they can log on a more peaceful character to get more constant roleplay.)
You can of course play a peaceful outlaw, perhaps a druid or a hermit, but you still lose out on most of the benefits of being in a town that I listed above. So I really recommend you have your first character be a citizen of a town and get used to the game before you try playing something as challenging as an outlaw, as the game engine itself doesn't favour them much.
This game is of course focused on roleplay itself, so if you want to play an outlaw, go for it. But since you are a newbie, playing in a town will make it easier to test out and get used to the engine side of the game, as well as make encounters with other player characters more common to get you more used to roleplaying as well.
Though all that being said: Welcome to Illarion!