@uehara, no, usually, when you login after such downtime, all plants and animals are revived.
The revival starts at your login,
But please note that the timer on all revived stuff is short. (don't remember if it's only 1 or 2 hr)
@archerbob, no, It will go above 41.
Along the way you'll encounter several ways to increase max energy, like the superstrength potion in the shop or the competition island.
@Sir_Gregor, the final quest is marked as "trigger", it means that the quest doesn't appear until you actually complete it. So you just need to feed the camel on desert island and you'll get the quest.