If I die before my divorce is final, will the property settlement in my legal separation stand?

It is really impossible to answer this question without more information and if you are really concerned about this you need to contact an attorney.

The answer depends on what you have signed--what is says, what kind of policy the children are the beneficiary of, whether or not there is an estate plan, etc.

I would suggest not worrying about your death in the relatively short period before this process is over.  You have enough to worry about.

Best of luck.