I started roundabout the same age, and I was also a mature student for the Masters prior to the PhD.
1) Like DocInsanity, I didn't have any children, so I cannot tell. However, some of my fellow students had children, and they managed very well - sometimes better than I! It might just be that they were better at narrowing down their research topic to fit a busy lifestyle. I was both more scattered and too 'thorough' (no regret though, I've done some great work ;)

2) All the mature students that I've met were, like myself, very motivated. With motivation comes hard work and success.

3) I too am trying to figure this out. With an usual academic path, and working in an area of Humanities which currently offers very few career prospects, I'm a difficult case and maybe not the most typical example. I graduated in 2013 and I'm still looking...I have to hold on to a day job in a call centre while also working on a monograph, articles etc at evenings and weekends. Overall, I think the situation is not great for postdocs (at least in the Humanities, I'm not familiar with other areas), but I should also admit that I'm in Ireland. I've only recently started to look for jobs in the UK because there is very little going on for us here. No help. Everyone says that there is no age discrimination, and maybe there isn't, but I still need convincing. I believe there should be more support out there for us. Once you're outside Academia, everything gets more difficult too. I think you'll have better chances in the UK. If I had to give one piece of advice, though, it's to start looking for postdoc positions and filling applications for Fellowships as soon as possible toward the end of your PhD. I hope this helps.