In the first episode they specifically ask Janet what the Bad Place is like and she says she can't talk about it. So whether or not Janet "knew" she was in the Bad Place (since she's basically a cosmic Google it's hard to tell how sentient she really is), she couldn't tell them.

If we assume Michael's flashbacks are truth, then we know he was an apprentice (presumably to an architect). So we know that architects have subordinates. Wouldn't it make sense if Trevor was Michael's apprentice?