You played wow? I started on regnum then, two years ago, left and played wow. Just returned to regnum at Christmas. Soon as you asked about addons I thought hm, that's familar. Much of what you post sounds familar to me.
Welcome to the game!
S'far as I've heard, nothing like questhelper, carbonite, nor any other addon works here or is in the plan. As for quests, there's a wiki page dedicated to regnum and so far it's been an accurate resource. Gems you had explained. Mounts are by purchase only. Clans (I still think of them as guilds) are in each realm and worth checking into. You'll notice lots of similarities between wow and regnum as I believe ngd fashioned a great deal of the game on the original blizzard designs.
Which realm did you join?