Hi Just Right,
That’s good news … and I’m really glad to hear it 
I think both of these are good suggestions. Post #3 here also has some suggestions that may be helpful and if you do choose to encase your foundation in plastic I would make it at least 5 mil thickness of clear non toxic polyethylene. If you have a foundation made then I would make sure that any glue they used was of course also non toxic. The plastic would reduce airflow between the mattress and the foundation but this would probably be a worthwhile tradeoff in your case.
I would think it would and some of the KD foundations in the foundation thread here may be worth looking at. Some of these already come with a cover.
Phoenix