What do you mean by "classic amx_who plugin"?
I found a custom amx_who command that I helped someone with way back that looks like it has the last part of your request
here. Try this one out (the one in my post), modify the category names and flags as needed. It might be a good start to add other stuff.
Regarding the permanent nick name, yes, that is possible. I even created a plugin to create
an API to do this.