Well first of all Greetinga and welcome i hope you will have pleasant time around
Now onwards to your questions
1. You can be renegade wizard, or try to join order. When you try to join order of high sorcery is completely up to you but more powerfull you grow more eyes will look upon you and one day you might be forced to make that choice, or even get killed for not making it sooner. There are players that are part of Order, if you decide you would like to join order i suggest you send them PM via forums.
2. I dont think choice of class is that limiting. You can start as pure cleric if you would like (but cleric class needs DM approval, so if you choose this route write PM to some DM with short bio of your character etc), or as knight of crown or any other class. I would say choice is up to you.