1) No.
2) Since trial and character is tied to your SE account, not Steam, so buying from any retailer is fine and you won't lose progress. Only way to get Steam version is on Steam
3) Mogstation - https://secure.square-enix.com/accou...vc/mogstation/
4) If you want the bonuses right away, the only way is to purchase the prepaid timecards and add the codes. Since the 30 days sub you get with the purchase of the game does not count to RAF bonuses, you would need 2x 60 day codes for whoever referred you to get all rewards (Circlet, Pendulum, Mount) or just 1 for your bonuses (Circlet).