perhaps this secondary angle will help

yep

I think this is a different one but hard to tell - they grow quite fast but on the other hand there are at least three different individuals I see from time to time

probably, Bunnings sell pipe in 1m lengths although easier with a car obviously - to save carting gravel you could just use dirt in the base

no power tools required for this, just pvc pipes stuck in a pot full of gravel - maybe a hacksaw or similar to cut the pipes to different lengths