Yes, it is possible. Need more specifics on probation and timing, however.

What shouls i do?

Please try the question again.

Empl app question asks: " Have you been ever convicted of a crime other than traffic infractions?". Do I need to include my DUI?

Yes. But it may be possible to expunge the DUI.

In which court setting (family, civil, small claims) can I sue my husband for a breach in a child support agreement?

Go back to family court to enforce the pre-existing order

Will return receipt on certified mail help me prove my spouse is receiving the certified mail but just chooses not to sign?

Yes.

If my sons father has not had any physical contact with him for over a year is that enough reason for sole custody?

Yes. Plenty.

You complained about his activities and the law took you up on it. What is the question?

How can I get regain custody of my daughter? Her grandparents from her fathers side have full custody

You have to contact a family attorney and discuss it.

If you plea not guilty, what can a public defender do?

Nonsensical; No idea

An investigator came to my home and threatened me if I did not confess what he wanted me to.

I cannot figure out what it is you are asking.