Curt, How did you lower the humidity. Removing the damp carpet had to help but did you add dehumidifiers to the hvac equipment.Improving the filtration equipment would also have a huge effect on dust mites.

< 50% humidity, HEPA air filtration and an electric blanket on the bed (on during the day) should help after a few weeks.

So far I've lowered the humidity via reduced airflow and supplemental portable dehumification.

My concern with the carpet is less about its dampness and more about its tendency to breed and house dust mites.

I don't think HEPA does any good with dust mites - they aren't airborne.

The issue isn't with the dust mites themselves, it is the allergic reaction to their droppings. These will stay airborne for some period.