Looks like you are off to a great start. Some of the comments and dimensions are hard to read in the drawing when we try to increase the size. Also not sure what your lot restrictions are, but here are few thoughts in response to your 3 questions:

1) Consider reconfiguring the master bath/closet/laundry (perhaps by moving your exterior walls slightly). The current layout looks a little tight in some areas, particularly for accessing the shower. The access from the master closet directly into the laundry is also a feature we add in our plans when possible so that is a nice touch if you can maintain it. Closet facing front is also likely a good choice - just make sure your windows are high enough to add light while maintaining privacy since it will likely also be a dressing area.

2) Most design software has sample furniture (similar to the DR table you have pictured), which will allow you to assess your plan against something similar to the furniture you have.

3) Another option for accessing the deck (depending on your final price point) is to add retractible doors along the living room wall that can be opened for an indoor outdoor entertaining experience in the summer months in the midwest.