I'm not sure if this is your problem (a lot of confusing text to read) but note that in Lithunwrap you have to be in Group selection mode to assign materials to models. That's one of the buttons toward the top right.
I recommend you get Ultimate Unwrap. It's not much money and, among many other things, it saves you from headaches like this.
I recommend you get Ultimate Unwrap. It's not much money and, among many other things, it saves you from headaches like this.