Support payments after separation if she loses her job?

Nope - you have the child the same amount of time. It’s up to her to provide income the same as you. And if she gets fired due to a drug problem you should be going for full custody anyway - your kid doesn’t need a drug addict around.

Depends on your jurisdiction, lost, but I think the possibility is high. In Missouri, both the three years that have passed since the original order (I presume there was a legal finding that said "no support") and the possible change in income of the mother would be reasons to review the case for modification. If your "no support" order was initiated in a court, however, it will have to go back to court to be changed and you will have your opportunity to present your side.

She could file for child support at any time. It would be wise to keep track of all of your expenses related to caring for your child. If she has a drug problem then you may want to file for sole custody for your childs safety and well being.

I live in Ohio. Same situation as you. I do not pay child support or spousal support. BUT if either me or my ex wife fall into life changing situations: ie one of us looses our job or on the other side of the spectrum, we get a raise or higher paying job, back to court to even things out. So yes, I believe she can. Just to give you an example- My ex and her MARRIED lover sent porn to my work place. I got the married lover to confess via e-mail. My first reaction was to forward his e-mail to his boss since he works with children. I consulted my lawyer first. His advice was if he drags your ex down with him, be willing to pay child support and spousal support. Needless to say I let it go.