"Four window layout" or "four windows layout"
To indicate a multiple object layout should I use four building layout or four buildings layout? Maybe they are both correct?
Similar to a 16-foot drop versus a drop 16 feet long, it would be:
Four-building layout.
Layout consisting of four buildings.
I think you've answered your question in your question by referring to it as a "multiple object layout" rather than a "multiple objects layout".
That being said, drop the s. You are describing the layout, not the individual elements.