Can we take care of all the paperwork at once?

What is the name of your state? WA

My husband left when I was 3 mo pregnant, I am now moving to WA state and know I have to wait to file for our divorce. My ex has agreed (adimently) to sign over his parental rights to our new son.
Should this be a separate petition - or part of the divorce process?
If it is separate, would that make the child custody paperwork unnecessary?
He has threatened that if I request child support (don't need) he would request alimony (don't care). If there is a problem with the process and the courts still insist on the minimum CS (until his rights are revoked) can I refuse that?
Thanks for any help you can provide.

For starters, you need to find out if WA will permit voluntary termination of parental rights w/o a stepparent willing to adopt. Generally, courts do not like to leave a child w/o two parents liable for support, for a variety of reasons. This may well be something that you CANNOT do.

A possible option wrt support is to come to a written agreement to refund the CS. Of course, unless it's ordered by a court, it's not binding on you.

Where will I find this

Is there someplace on the web that I can find out about the WA state law on the matter of revoking his rights?