Again, given the nature of your extensive search for a full financial analysis of your situation, and options, your choice of transaction simply won't work. (It would likely take hours of work.) As you can see, it is extremely TIME CONSUMING, which isn't a problem, generally, but you will have to go piecemeal, given your choice of a transaction. So while I sought to explain to you, as per your question, HOW you can go about doing this (ie. do the math), perhaps this is better. I now see your first question to be:
Is the child credit based on my full SS benefit at 66 or is it based on the windfall amount?
I will answer that question and provide supportive citation. The child dependent benefit is based on your benefit amount - so if WEP is applied to you (once you start taking the pension) then all of your dependents taking will be affected. Note that if you die, WEP is no longer applied to your benefit (since you no longer get a benefit) and so survivor benefits to spouse/children are NOT effect by WEP, but on you full unWEP'd benefit amount.
You can then go piecemeal with a new question, one at a time, asked and answered, before moving on to the next. The alternative to that, is an actual consult which, after this question, I could point you to where to go to sign up for same - but that is not the same price as here, obviously.
So, since you indicated, "In order to do the math, I needed the answers to some very specific questions" - please tell me. Do you want to start doing the "specific questions" one by one? We complete one, you choose or not choose another. Or, you ask to have access to hiring a consult - that is up to you.
In any event, I have now answered a second question, shown in bold, above. And yes, that it more specifically asked and answered.