WOW Gold: You will only gain one bonus for changing class at 30 and 40
The weapons you choose will also affect the beginner melee skills you'll be using WOW Gold, since there're specific weapon for offensive skills.
Q: If I change to another class and unlock the tier 2 or 3 skills for that class and then change back to the original class I intended to go, will I keep the extra skills I gained?
A: No you will not retain the extra skills you have gained unless you remain as the class you gain them from.
Q: Would you receive the level 40 "items", like for example could you choose Isis if you went Warrior->Summoner->Grazier?
A: Yes they would gain Isis if they did this.
Q: What is the "max out their xyz PT" for pure Specialists? I have yet to find a site with the information on that.
A: A specialist as long as it is not cross classed will be able to get all of their PT's to GM/99 just like all other Pure Characters.
Pure Character: A Character that has not deviated from their original classes tree e.g. Spiritualist -> Summoner -> Grazier/Dark Priest
Q: Can I gain multiple bonuses for re-defining and choosing my classes again?
A: You will only gain one bonus for changing class at 30 and 40 (so you will keep the first but not gain a second bonus).