Is there any way to import a two dimensional floor plan into Augment

Technically no but you can do it relatively simply. Bring in a Square shape from the library, Import a photo of your floorplan into Materials, set that as the material for the square, set the repeat texture (or equivelant) to something tht means its shown one itme on the plane, adjust the planes size to meet your plans aspect ratio. Then add a cube or square object, set the size to say 1m, and reference that to something that is meant to be one meter in your plan, scale up and down accordingly.

Technically no but you can do it relatively simply. Bring in a Square shape from the library, Import a photo of your floorplan into Materials, set that as the material for the square, set the repeat texture (or equivelant) to something tht means its shown one itme on the plane, adjust the planes size to meet your plans aspect ratio. Then add a cube or square object, set the size to say 1m, and reference that to something that is meant to be one meter in your plan, scale up and down accordingly.