This isn't sexy but we now have 6 starters. I'd keep my eye on another one and push Chavez to a swing man role or sign a solid swing man and leave Chavez in the rotation. With 6 or 7 capable guys that should keep us in the hunt til the trade deadline at which point we could trade for a top of the rotation type.
The AAV for Happ is low enough that we can still keep adding depth. I think this team is a clear favorite in the AL East but with an old team and no depth injuries could ravage us. The depth concerns are already getting cleared up and it isn't even December yet.
Just keep hitting singles all offseason instead of going for the home run and I think we will be fine for this season and better off for the future.