First, I would suggest making a component of the thing and then use the Dave Method to work on a large copy of it. This will help you avoid tiny face issues.
For the chamfer, select the outer edge, get the Move tool and while holding Alt to invoke Autofold. Move the edge down toward the brown face.
To fill in the missing surfaces, use the Line tool to stitch between vertices. on the curves. Then hold Ctrl while clicking on those edges with the Eraser tool to soften them.
FWIW, there are extensions that can do these things but they are so trivial with the native tools, it hardly seems worth bothering with extensions.
By the way, you should get in the habit of correct reversed faces as you go. There should be no exposed blue back faces in your 3D model. Save applying colors and materials until after you are finished modeling.
Also, it would be a good idea to get in the habit of dragging out circles on axis so that you don’t wind up with misaligned vertices. That can create a bunch of problems for you down the line.