Best I can do at this stage:To be fair, I don't think any of the above will come into fruition. Those appear to be completely quick mock ups with no design to them, to show an idea that they will change something. For example, that replay screen is a mess of a spot and the titchy little extension that you suggest would bring the permanent capacity to 27,000 are just jammed there with no real order. There doesn't seem to be any actual design in them yet, but i suppose we'll have to wait until they release the plans in a couple of years.
I doubt the suns will have any problems playing there in 2017 though (unless they demolish so much that capacity is two men and a dog), it's more than easy to demolish a stand and still play until they place the athletics track in. MCG didn't lose any time; KP, bellerive, SCG
You can see those plans show two screens opposite each other and extra seating being installed between the light post and the corporate area. The large temporary grand stand is of course between the two northern light posts. This render also show the screen being moved to the east to make way for the grand stand: