Married and Divorced in Abroad! Financial Responsibilities in USA?

There's not enough information in your posting to answer the question. Child support is highly likely.

Can my ex-husband have my son's last name changed?

He can not accomplish a name change without your consent...period.

Can I amend a divorce decree on line in Manhattan NYC

No. You can't amend anything in divorce online.

I've recently divorced on the papers he put their was only one child born in the marriage but we have two? Is that legal

It's not illegal, even if it's technically wrong. A local attorney will be able to advise you as to the appropriate response... which may be that...

You can't get a court to waive a statute of limitations. But she may be incorrect as to what effect, if any, the statute has. Consult a local...

My husband lied on the petition for divorce papers saying theres no children when we have 4 children together what should i do?

You hire an attorney to file an answer.

It means you have advised the court that there is settlement agreement and the court is either waiting for or has received your documents, but...

Hi. after having an attorney for over a year, after doing all the work, they suggested, bc i could no longer afford them, that

The settlement agreement and all the other papers needed to finalize a divorce can be a substantial package. You should consult a local attorney -...

As the Petitioner, do I have an opp. or right to respond to the declaration from the respondent in a motion to set aside default

You do have the right to do so - whether you should or not is a different question.

Im getting a divorce and the house mortgage is in my name but her name is on the deed.

Unless the transaction is reviewed in advance by your attorney you should sign nothing.