Sounds like you've got the bulk of it. There's nothing hidden, no secret methods to survive.
But then again... "Goddamnit, you've got to be kind." ~ Kurt Vonnegut Jr.
So, all I'd add is that the world is difficult and chaotic and hard and all we have is each other. So, take a moment and think about how to serve at every opportunity.
> should we ensure food security by stockpiling long-life foods and water sanitisation methods, how do we ensure energy security, how many years of self-sufficiency should we prepare for etc
i've never tried to do the self-sufficiency thing myself, but from reading a few books about it: it is very hard to become completely self-sufficient. It is more realistic to aim to become partially self-sufficient, and develop strong ties with your local community. E.g., if you get seriously sick or injured, and there aren't functioning institutions, who is going to help you? Your family or your neighbours.
What skills or resources will you be able to offer your community in return? enterprise software development? not very useful. Skills in low-tech medicine, farming, construction and repair with hand-tools, a bunch of surplus vegetables? likely far more useful.
> ensure food security
not sure if this is a helpful comment, but: i dont think it is realistic to be able to ensure security (food or otherwise) of any individual. diversification helps -- may be able to ensure security of the species, if not individuals.