Only played the Dreamer once, but a couple thoughts:
1) Not sure of his playstyle, but with the Outcasts it can be really easy to split up your crew a lot thanks to specialization and varied mobility (the Viks are fast, others not so much). This lets Dreamer pick him apart piece by piece; far better to stay somewhat close together so that everyone can jump on whatever you drop out.
2) I would absolutely drop bishop. I know not everyone agrees, but he doesn't do it for me. Add another Ronin, and maybe a convict gunslinger to put out some ranged fire. He might try making the gunslinger and librarian a center for a castle with the Viks, Taelor and to a lesser extent the Ronin staying w/in 8" of them in different directions as needed by the scenario. This way there's some fire support (in Rapid Fire) and healing generally available to everyone who might need it.
3) I usually try to keep one ronin safe and alive to summon another Vik if need be.
Just a few thoughts, although like I said, I'm not used to fighting th Dreamer, so I'm sure someone more qualified on here has better thoughts.