The 457(B) account most likely cannot be used as proof of supporting funds as it is not readily accessable like a checking or a savings account is. It is still considered a pension or a retirement fund for the purposes of visa applications.
If you have defaulted on the home by the time of your application then I would assume that technically it is no longer owned by you but by the bank.
There are a lot of 'what ifs' and 'maybes' in your current situation. Perhaps it would be best for you to sort yourselves out with your financial situation first and then see what situation you are left with when you get closer to the time where you'd actually be applying for your visa.
I used to work in Welfare Benefits Determinations & Fraud division when I lived in California in my previous life and I always had my clients asking me about things that may or may not happen and how that might affect things. My standard response would always be 'I cannot determine eligibility on a hypothetical situation, I have to take things as they actually are. So when and if the situation changes, let me know and I can tell you how it will affect you, if at all.'
So, it is probably best to see how your situation settles in the end and then seeing what type of a position you're in for a visa application, when and if that time comes.
I'm not trying to be flippant or dismissive, it is that there are just too many hypothetical variables that do not lend itself to clear answers to your questions.
I fear that I am venturing into waters that I am not qualified for and that at this point I am going to suggest that you see professional advice.