The mattress is 19"x19" and folds down the middle, it is stitched twice about 1" apart down the middle. Then each side is tufted, just tied off, evenly spaced two rows with three ties each. The bedspread is 21" x just over 19 3/4" not measuring the trim which measures 1" wide on three sides and stitched on the outside. The pillow is 4 1/4" x 7 1/2".
It does have stoppers on the legs which would keep it from scratching but not from sliding.
It comes as one piece so not sure what you mean.

Hope this helps, good luck, it is the cutest bed.
Mary D