Hi @KSJ ,
A combination of what you’ve listed but without checker brooding 
The logic of putting a new box under the existing brood box is based on the natural tendency of bees to expand the nest down during the growth phase. However, you do still have quite cold nights and the queen could be reluctant to move downwards if there is room for laying in the upper brood box. It is warmer there. Eventually, they will move down and will begin to use this box, so you can do this, but as @Dawn_SD said it is extra work with results that can be achieved with less effort. If you want to intensify brood production and combine it swarm prevention step, then, yes. It is worth the effort, but it includes confining the queen to the bottom box by an excluder. This is an intensive method of beekeeping that involves constantly moving empty frames under QX. It works wonders in both swarm prevention and honey production in short intensive nectar flows. A bit more about this here.
But if your goal is as simple as increasing the size of the hive, just put a box of frames with foundation on top and walk away. You may promote things a bit by moving a couple of frames with open brood in the middle of the top box. It will make nursing bees building adjacent frames. Add a couple of frames with the foundation in the middle of the nest in bottom box to break it and to keep bees busy with repairs to reduce the chance of swarming somewhat.