Because we are adding more thickness to the wall, we had to rethink our exterior trim. Originally we were wanting a 3-1/2" wide trim that would be picture framed around the window, but after mocking it, we came to re-evaluate this due to the multiple 12 steps to building it out versus 5 for the 2x on end. 12 x 34 window groupings equal a painfully slow process. So we decided we liked the more streamlined look.
You can see all the extra blocking needed in this side shot.
We also briefly looked at adding a stepped trim piece around the frame, but decided against it's fussiness.
We have tried to minimize the fan vent locations and while we do not have individual exhaust fans for our main part of the house, we still have them for the apartment portion. For every hole coming through from the inside to the outside, Neil has boxed it out and flashed it like below. All of the vents, hosebibs and exterior electrical outlets receive this treatment.