The bubble adjacent to the plastic boxes should say Single gang. Also the staple can be 12" when the plastic box has an integral clamp. Without the integral clamp then the staple must be within 8". It would better if it said: Staple within 8 inches from plastic single gang boxes without an integral clamp.
334.30 Securing and Supporting.
Nonmetallic-sheathed cable shall be supported and secured by staples, cable ties listed and identified for securement and support, or straps, hangers, or similar fittings designed and installed so as not to damage the cable, at intervals not exceeding 1.4 m (41∕ 2 ft) and within 300 mm (12 in.) of every cable entry into enclosures such as outlet boxes, junction boxes, cabinets, or fittings. The cable length between the cable entry and the closest cable support shall not exceed 450 mm (18 in.). Flat cables shall not be stapled on edge.
314.17(B)(2) Conductors Entering Through Cable Clamps.
Where cable assemblies with nonmetallic sheathes are used, the sheath shall extend not less than 6 mm (1∕ 4 in.) inside the box and beyond any cable clamp. Except as provided in 300.15(C), the wiring method shall be secured to the box or conduit body.
Exception: Where nonmetallic-sheathed cable is used with single gang nonmetallic boxes not larger than a nominal size 57 mm × 100 mm (21∕ 4 in. × 4 in.) mounted in walls or ceilings, and where the cable is fastened within 200 mm (8 in.) of the box measured along the sheath and where the sheath extends through a cable knockout not less than 6 mm (1∕ 4 in.), securing the cable to the box shall not be required. Multiple cable entries shall be permitted in a single cable knockout opening.
The maximum degrees of bend is 360, which does not need to be only 90 degree bends. Lesser bends all count towards the 360 degree total.