Never heard of a plastoid, but the name sounds pretty alien so it seems we're [i]all[/i] a bunch of weirdos lul.
I personally find Echo Knight the most interesting of the list if you're worried about overlapping(it's a very fun subclass).
I'm making an Artificer too, but [i]honestly[/i] could not care less if you also play a machiney boi/grill, they will be different regardless.