Re: Elastic stretched and diapers leaking! Why?
I think Charlie's and 1/8- 1/4 C bleach (for an HE front loader) would be fine. I think the heat is what is doing the most damage (get rid of the sanitary cycle and just use regular hot) and seriously reduce your dryer time to maybe 1 hour on medium...then air dry rest of the way on a flat rack. I would not combine oxyclean and bleach either....it's just too much. I'm surprised the PUL hasn't started to delaminate with the sanitary cycle as I've heard that can happen.
Elastics are just going to need replacing in diapers because they are so frequently washed...so don't beat yourself up too much over it. They are diapers...you do need to get them clean. Sorry that this is happening to you though...hopefully you can find someone to replace the elastics.