Where is Edwin at or available for your party and when in the game if I have to wait? I am in chapter 3 at the moment and trying to stick with neutral and evil party members. Thanks!

do the Maer Vear inflintration quest

In case you are not sure what Jon means, you need to go to the docks district and go to the shadow thieves guild and accept the quest. After you complete it Edwin will go to the Copper Coronet and will be available to join your party.