Keep in mind that these quests are optional, and are not necessary to continue leveling and capturing companions. They are also account-wide, so if you complete the quest chain on one character, you will not be able to complete it again on another. However, any progress that you've made will be saved and you can pick up where you left off in the quest chain on another character. The dailies that you've unlocked will also be accessible by all your toons.
Oct 24 A Return to World of Warcraft: Player Guide So you’ve decided to return to World of Warcraft. Welcome back! There’s just one thing you’ll need before jumping back into the fray—knowledge. To aid you in making your glorious comeback, we’ve compiled some handy information every returning hero should know. Once armed with knowledge, nothing (and no one) will stand in your way. http://us.battle.net/wow/en/blog/8876440/Nethaera214 Oct 24
Beginning May 15, select WoW players will be invited to participate in a small-scale, focused closed beta test. Players will also get a chance to help put our servers and technology through their paces in a series of stress tests running from May through July—you can opt in now through Account Management and select the WoW Classic beta. Subsequent stress tests will extend the opportunity to even more players. Level caps will also be in place to ensure we’re emphasizing the “stress” in “stress test”