Thanks for the comments. We are presently engaged in an effort to answer the question regarding the right planting knowledge. It is nascent and I will share details about it if it bears some fruit and at an appropriate time later…
I do not want to take a very hard or purist stance, except for some areas that have high conservation value. There is still large areas, incl. human-use landscapes for a lot of middle ground. The main point is to widen the net of species to more natives as far as possible, rather than more easy/familiar non-natives.
Your third question has to be answered in context of specific areas/landscapes. But this paper might give some ideas of what would be the reasoning or approach:
When is a ‘forest’ a savanna, and whydoes it matter? https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1466-8238.2010.00634.x
Trees as Nature-Based Solutions: A Global South Perspective
Trees as Nature-Based Solutions: A Global South Perspective - ScienceDirect