As per another comment in this thread, I really want/like links to original sources for figures, not second hand reporting.
But let's accept some of those reports on face value. In Australia, you have to take into account both that we have laws that limit foreign purchasing of established properties, and that those figures are commonly for newly established properties.
Firstly, that's exactly what the policies were supposed to cause.
Secondly, new sales need to be measured relative to turnover and funding within the local established market. This gives you an idea as to the relative scales. Under the observation that many of these investments will be in high rise inner city apartments, again, it's not necessarily such an alarming figure, and arguably, might even be what policy was set out to achieve.
The most feasible take away I think is your link no 6:pointing out that the price set in a market is a complex play of expectations and marginal prices.
But, as with most of these articles and points, this all had to be taken in context of the behavior of locals and he size of their operations.
I don't say that foreign investment plays no part. While no rain drop considers itself responsible for the flood, I think it's a curious analysis and interpretation that focuses on the 10% and blames them, when there is enough explanation to be found in the behavior of the local 90%, given that obviously market outcomes are in truth an interplay of both.