What are my best options of starting as a fresh multiboxer?

[aviationizhere]

After taking a long break from wow playing single characters I'd love to start boxing and be ready to level in cataclysm. My old account has a 80 paladin in some hateful ret / holy gear, and a 80 druid in some hateful resto gear. Would my best bet be boosting my boxing characters in instances while they are on refer a friend or would questing with them be faster? From what I've read you need a prot pally or other tank to boost efficiently and I don't have any tanking gear for either class.

I'd love to make 5 elemental shaman but know it would be more difficult to get them all arena gear as that setup doesn't work as well as 4 elemental / healer. Is it possible to add all 5 shamans to a 5v5 team and play enough games per week for points on the 5th shaman? Lastly how effective are 5 elemental shaman at PvE in general and at what point will you need to start grouping with a tank to clear content? Thank you in advance :P