No, although the debt will be sold on for pennies, you, as debtor, still owe the new owner the original amount (that's how they make their money).
One, possible, upside is, because the new owner has a much smaller outlay to cover, they will be more open to offers later on if you get the chance to make a F&F ---- pure supposition there --- depends upon how greedy they are !
My opinions are merely that .. opinions based on experience. Always seek professional advice.
IVA Completed 23rd July 2013 .... C.C. 10th January 2014
You don't necessarily need to, unless the IVA fails and you have to deal with those creditors again, but if an assignment of the debt is made, them the creditor should write to you to inform you of this.