OK. Everything seems normal, seeing your screenshot. What is displayed in the Scarlett 18/20 USB pane ? In it, there should be listed all the inputs and outputs of your device, with added settings.
Beside this, I would say that hearing directly the dry sound without any plugins processing could be related to the Direct monitoring being activated. Does the Scarlett driver allows direct monitoring ? if so, check in the Scarlett 18/20 USB pane to cancel it, if needed.
These don’t solve the ‘ASIO driver isn’t running’ error, though. What is strange is that indeed, an installed ASIO driver isn’t relevent for an OSX based system to work. So, at this point, I’m afraid that I can’t help more… 