if the jointHierarchy fits all different geometries the same way that would be no problem. create a empty group by selecting nothing and do a groupOperation. select the rootjoint (or root CTRL_object) from your rig and MMB drop it onto the nullGroup. this prevents the hierarchy from geting destroyed. duplicate the rigs.

after that place your geometries in the right place and smoothBind each animal to hierarchies. I fear paintweighting is still a task which can´t be left out. but at least you don´t need to rebuild your rigs. good luck!