Is an echo knight’s manifest echo a snapchot of your character when creating it or does it change with your character?

Lets say you pick up a fallen enemie’s weapon, does you echo knight instantly get that weapon as well or do you need to make a new echo first.

And what about changed to your body, like a multiclass in druid with wild shape or a changeling that changes how they look.

Basicly : Is the echo always a reflection of your current body or can it be different.

Im interested in both the visual and mechanical implication of this.