I think my answer to the first part would be a little too real-world for what the test is looking for, so I'll refrain.
As for design guidelines, the focus on architectural style and look/feel is the main point.
From Planning and Urban Design Standards (Steiner): "Urban design plan reports often contain a section on
design guidelines, including massing, height, building
setbacks, architectural style, parking, streetscapes,
signage, materials, and sustainable design." Some of those, especially height, setbacks, and parking, are typically thought of as zoning components. This article does a good job briefly explaining the difference between zoning, design guidelines, and form-based code (it's an opinion piece but the info is useful):
https://formbasedcodes.org/articles/design-guidelines-dont-work/
Other possible criteria for design guidelines are listed in LaGro, hopefully a citation will make this okay to post:

- Extension of the programming process, intended to enhance or maintain the visual quality of neighborhoods, business districts, and other areas
- Not site-specific, typically portray the desired qualities of design solutions
- LaGro, J. A. (2008). Site analysis: A contextual approach to sustainable land planning and site design. Hoboken, N.J: John Wiley & Sons.