if you keep the shaman as a caster you should be just fine, It'll stand with the mage at the back and the paly will be alone at melee range.

totems are easy enough to manage, just get your favorite set and drop it when your paladin does his avenger's shield or whatever pre-dps spell he does :-)
Mage casting, depending on the spec, is very simple and can be summarized nicely in a macro (see wiki)

Not sure what your concerns are?