Arcane Mimicry and Echo interaction

In particular, is there any in the case that I Arcane Mimicry and Echo off a team mate. When the Arcane Mimicry duration ends, will the Echoed skill turn back into Arcane Mimicry? Will anything special happen when Echo's duration would normally run out?

the echo will act like it does not know the existance of the arcane mimicry or arcane thievery, therefore... it will depend on echo to last.