i've never played shammys but i do have a warrior/pally for melee and a priest/lock/mage...

I have a formation key binded for the casters that makes them stop following, for the melee guys i use a

/follow macro and a /assist macro and turn on the check box in the interface options that makes them auto attack when they assist...If someone gets turned around i just get the position right on my main and hit my /follow macro and /assist macro (they are 2 seperate macros, works better for me) and the pally turns around and starts attacking again...

As far as the rest of it i dunno really, hope that helps with the melee part though.