Not updating the TOCbin for the basegame and DLC your edited could be causing infinite load issues.
Keep in mind that when you swap meshes, you'll have to do so for all instances of them in the gamefiles for changes to be consistent, while sometimes a mesh will only appear in a single PCC, others might show up in over 10-20 different PCCs and will have to be swapped in all of them.
Also, while you can use PSK export, you'll have to use UDK import, so run your exported meshes through the UDK before putting them back into the game. Additionally, all instances of the textures (diffuse/specmap/normalmap) will need to be swapped and you might need to do some work on the specmap if the material assignment between both outfits differs.
I'd suggest hitting up some tutorials on the ME3Explorer forums.