AFAIR you can equip the monocle.
Nope, it's a non-usable quest item...
Just to let you know, that guy who told you that is a Dev.
You can equip it by dragging it into your pockets like the Masquerade masks I'm guessing.
Got it too. No idea where from, no idea what's it to be used for.
I've honestly not encountered it yet. I'll see what I can do when I find it.
You get it from this quest
You can't.AFAIR you can equip the monocle.