The gable roof allows a fairly simple lateral expansion.

Expanded Design #3

Expandable #3

Comparison: The core plan for design #3, #4 share a generous side entry module. The more notable common denominator is the steeper pitch gable roof which effects a comfortable and conventional 'home' aesthetic. #3 has a more contemporary window and door treatment, and #4 enjoys a traditional rural farm house  treatment. As with so many smaller footprints the stair location sets up a lot of other planning.

This design: The simple exterior uses a steeper roof and the simple bay window and stacked small window theme to give these boxes some personality.  The stair location and windows are an important design asset. But the table and kitchen space is squeezed a bit because of the stair position. The living space on the other hand is extra spacious. The master suite expansion is necessarily bigger than the sunroom connector- and is free to take on any size and subsequent plan arrangement.

Style: As drawn this designs has a contemporary farm house sense. This same design, with a brick veneer, and grills in all the windows, would be right at home in a traditional suburban setting.