Absolutely they will. Keep in mind, if the other parent goes to court because you haven't paid child support, you'll be in contempt of court, which only works against you. If you ever come back to the US, you;ll be arrested at the border.
You can count on that.
A US state civil court cannot enforce a child support order in another country. However, as of October, 2006 any US citizen owing $2500 in child support arrearages will be denied a passport to enter or leave the US. http://dor.myflorida.com/dor/childsupport/ read it you can enforce it in Canada because we have reciprocal agreements. I am in the process of doing this you just need to contact the child enforcement office in your state or county.
Contact your local child support agency and see if they have an agreement with that state to enforce the order for support in your state. Some states cooperate with other states and will take action, some do not. Only your local office can tell you.
No. The issue of the children's mother being on maternity leave has no bearing on child support obligations. The money is for the children's care not for the ex-spouse.
yes
both of them
no
yes
no
Yes. The court will say to find a way to do it. This is your responsibility. They do not care about your medical leave, but you might be able to have the support lessoned.
possibly
if the child is 18 or over you shouldn't have to pay any child support at all unless you have back child support
You need a court order suspending/terminating support.