For arrears, yes. see links below
The State can place a lien on an IRA to collect child support arrearages, yes.
yes
yes
yup
yup
Yep
No, your salary cannot be garnished to pay the debt of another, UNLESS you have contracted to pay that debt. Now, that being said, any assests such as bank accounts, stocks, bonds, Certificates of Deposit, IRA's, etc. that represent mixed assetts of you and your husband can be attached for the solution of a debt, especially child support.
They can sometimes...you would need to check with your state laws to see.
In Illinois, yes, even if the child support obligor transfers his IRA into a new spouse's name. See Takata v Hafley at http://www.state.il.us/court/Opinions/AppellateCourt/2008/3rdDistrict/June/3070175.pdf
yup
No, the IRS does not have the legal power to take such action.
IRAs can be seized for child support. I suggest that you contact your State's child support agency. When you get an interview with them, bring all the papers relating to your child support: birth certificates, acknowledgments of paternity, court orders, payment records, etc. Be polite but persistent. Good luck!