1) Having played Warcrafts 1-3 would help you understand the game's story in detail more than having not played it. That said, it's not required that you play Warcraft 1-3 before playing WoW

2) If you die in the game, your gear loses durability. That's all, no exp loss, no character deletion, no item or money loss. Only cost is repairing

3) The original set is good enough. The expansion is a bonus and helps you to experience the whole game, but is not required. You can play the original game first, but without the added features available in the expansion; can't play Draenei or Blood Elf, can't play Alliance shaman and Horde paladin, can't go to Outlands, can't go past level 60

4) The original is a requirement; without the basic, you won't be able to explore the 2 main continents

5) Once you activate your account, it will always be available. Your play time is dependant on your subscription; 30 days, 60 days, 90 days or 1 year. You can play nonstop for the duration of your subscription period; 24hrs, 7 days nonstop. Once subscription over, have to renew it

6) Your character will remain where it is when you last logged out. Nothing changes. You'd only gain rested experience (helps to level faster) depending on how long you don't play your character. Even if you cancel your subscription, your character will not be deleted

7) Ragnarok wishes it was like WoW. That said, WoW is more in-depth than Ragnarok. Way more in-depth.