That is dependent of state laws and circumstances. In California, if a father files for a reduction in support, due to a layoff, than 20% of the income of the second wife or S/O can be used. See link.
husbands income does not count and is irrelevant
No.No.No.No.
The other party has to agree to that. In my case, I did that since I moved out of state. Long story short, I didn't have the prospects of the income needed to pay child support, so that amount was subtracted from my settlement from my ex husbands IRA.
There are too many related factors to calculate this, even with a known amount. Each state has its own guideline, and inclusions or exclusions on income and deductibles. Some use gross while others use net.
Get a subpoena.
Yes the amount can be based on your income.
The judge will be the one that will decide the how much if any income support you may be qualified to receive from the payer of the support amount.
Depends on your crime, but yes.
No.
probably not
no
That depends on the state see links