To rotate a model, hold alt+left mouse button. Also, you probably exported it as an xmodel_export without fixing the model so it work with BO3. You need to edit the "<file name>.mel" .mel file as done in the video and remove the BO2 joints. You'll need to export a BO3 model and keep the BO3 joints. Then, you can slap a BO2 zombie model on it
There's nothing wrong with Wraith, I just think you have screwed up somehow. Nothing wrong with that, shit happens when you try something new
Even I screwed up with my first weapon port (joints/model didn't matched eachother)
You don't need all the LODs as they take up additional HDD space and you don't really need them.