Long time lurker on this post, hello!
Just wanted to say I think you are AMAZING! You are found so well and your DCs are going to be so proud of you. Be kind to yourself and have a safe space to cry if you need to.
Also, just a layman but I think you should go for The Big Job. It sounds like it excites you more, pays more, has less travel and only slightly longer hours. I am combining an attempt at a Big City Career with small children, and if you find a good nanny or childminder or nursery you can do it all, it's manic and you never relax but it's thrilling and never boring and it makes you feel full of confidence and power and ability. What's the worst that can happen? You find it's too much and you have to step back to a less responsible job like the second one you're considering? :-)
Best of luck and I'm sure you'll be fine, more than fine, whatever you decide. Sure, there is a short term hill of grieving and adjusting to get over. But once you are reconciled to the new normal, once your subconscious settles into it then wow, you will be unstoppable!!