X-refs, extend command, drafting in degrees-minutes-seconds, creating custom line types

X-referencing. It would be helpful to be able to load models into each other, while keeping the original intact. Sketchup model A is a site plan with landscaping, utilities, hardscape, etc. Sketchup model B is a building. Model B would be referenced by model A, such that it shows up inside model A, but cannot be edited without opening its original model B file. When model B is updated, it also updates in model A. When viewports are saved of model A, they include saved views that show models A and B.

Extend Command:
In Sketchup, when two lines are drawn perpendicular to the other but not touching, allowing an extend command to extend one line to the other, until they meet.

Degrees/minutes/seconds: the ability to switch from drafting in inches/feet to degrees/minutes/seconds in order to accurately draft surveys. And then switch back to inches/feet in the same file.

Custom Line-types: really, it would be helpful to have sewer, water, fence, and other civil-engineering and/or surveyor line types. Whether they are included as a package or we have the ability to create a custom line type in Sketchup AND Layout would be very helpful. The workaround, currently, is to draft a dashed line in layout and then fill in the gaps with letters. This is terrible.