From what I have seen in the past, the set of people with children and a mortgage can be difficult. Some really do not want to be there, but stay for job security.
I'm also not entirely sold on prioritising those lay-offs based on social elements, such as children. I can see incentives being good to have more children in a society, but you shouldn't be punished for not having them. Ultimately from the company's perspective, you want to maximise your company's future success.
I would amend some points:
> Stick to your contract hours.
Do additional hours where required and you are able, but make sure they are visible, and compensate yourself them back. It increases your perceived value.
> Avoid going above and beyond with initiatives.
For your own sake, take pride in your work. Don't become stale.
> Always keep interviewing.
Many stop doing this because it's a pain and stressful. I think it is enough to keep your toes in, try to figure out what salaries are being offered, what kinds of jobs are available and how desirable you are. Try to learn those things with as minimal effort from yourself as possible.