Select all that is left using the “Selection by Name” icon and create another selection called Helpers, and hide them too.
Now we call back the mesh just selecting it on the name of the selection, a warning box will appear to tell that the objects of that selection is hidden and asks if you want it to bring them back, click yes.
Now we have only the 4 meshes on the 3d scene, it is a good time to save your work.
There is a problem with the uv map of the model, the texture is not in the right place, but as we are not going to use it anyway there is no reason to worry.
One important step is chose the right base mode for the model we are going to merge, in the model we've choosen (pmbil) the feet and gloves are separated from the whole torso, so the mesh we are going to add must be separated the same way, otherwise we will have problems with the bones as their configuration fits how the mesh is separated.
We can use a model that already have the same separation, Carth's cloths for example would fit well as it is separated the same way, or we can remodel our model to fit it.
Here I remodeled Carth's cloths to fit his underwear bone configurations.
That is how I load the base model, in part II we will see how to import and merge the new model.