Population growth is not a massive problem: we already know that human population will hit a max of 10 billion people and from there start aging progressively and reduce over time.
I agree. The problems are resource consumption and pollution per capita. There are many soft and hard effects trends that are reducing population. Oceanic food production that would also sequester carbon would allow for a greater population carrying capacity. The main issue is getting people to reproduce. xD
We don't know, we suspect that in the most optimistic scenarios. Without knowing the underlying mechanism. Without knowing the consequences of cultural change and industrialisation of the third world countries.
This is the finest kind of denialism, and it is really going to bite us hard in about a hundred years at most.