It seems to dye well, the hood the one independent of the costume the hood part seems to be dyable however it the second part those little gold things on the side seem not to be this is for the hood not the costume. Also wished major adornments as they don't show. I think that should be added to the hood plus the costume hood. As it doesn't make sense for those to be disabled.

I guess I'm safe to assume that the lantern doesn't cast any light?

The latern does not emit light, not even fake light. The latern is just turned off.

It also does not dye very well. I suppose this was not necessary to make, since graverobbers usually look filthy.
I wanted to use this for treasure hunting in Greymoor though, since it looks more like it than the actual treasure hunter outfit.