Mesh split while posing

Fairly new to blender but wanted to try animation after getting the hang of modeling. After hunting around online for a model that would be fun to work with I started working on basic rigging and weights, ran into an issue that splits the mesh when moving into a default t pose, I suspect that it may be related to the fact that I grouped the meshes together before creating the armature but would appreciate any help/nudge in the right direction.

https://1drv.ms/u/s!AlMyR-B3DhP2aFLoRhMIeh1EQcs

The hair parts and glasses are duplicated three times, so first remove those duplicated parts. Then select all and remove doubles (W > Remove Doubles), that will remove the cuts in the mesh.