All specific parts are separate mesh objects. As with all of my models with any detachable,  unique, and independent mobile asset, I model, rig, and animate these parts independent to each other. This model is no different. This makes it much easier in exchanging and switching parts as well is more memory conservative that just having a different, specific model for each cosmetic change.    

Besides the use of Rigify for the character rig, then no.

The modeling and rigging of the character was in fact not intended for explicit projects in mind. It was more of being a perfectionist. I've been around the block and seen many ways people will use models in their 3D projects~ And I mean MANY WAYS. So if you work in THOSE WAYS then you could use it for that if you want, I guess?? 

A side from giving credit to me for the use of the model in its raw form, then yes. If you customize the model to an extinct that it is far from the original, you are not obligated to credit me in any way in your project, though it would be appreciate it if you still do.