I was diagnosed with dust mite allergy as a child and all my parents did was replace the carpet in the bedroom with hard flooring and replace the feather pillow with synthetic. There is a school of thought that says making our environment too clean and sterile might be contributing to the increase in certain health problems. So don't feel you have to rush to update the whole house. I'm not even sure what difference the paint (on your list) makes? (Low VOC is best but that is unrelated to dust mites.)

Take the time to do some research and also seek advice from medical advisors and allergy support groups, there are aspects of your question which are probably better answered by other parents in a similar situation rather than by people on a decorating forum.

Keep up-to-date with what's on the market, there are products which didn't exist when I was a child which might well be useful for you, but also be wary, don't feel you must invest in every new product that promises to do amazing things.

Dust mite allergy is allergy to dust mites, which live in dust, so what you want to be doing is reducing dust.

The list from Brandi Nash Hicks is a great start. Make everything easy to dust, for example enclosed storage rather than open shelving, streamlined lighting rather than ornate fixtures. Use dusting tools that collect and remove the dust rather than simply sweep it off (I was going to give the example of static cloths but they're not appropraite in all situations, you're not supposed to use those near electronics). Get a good vacuum cleaner with a HEPA filter. I guess it's hard to say no to stuffed toys but store them inside something and vacuum them often. With large expensive items especially, weigh up your options before replacing them. For example a good quality fabric sofa might not necessarily be worse than a leather sofa, depending on various factors including leather quality, your climate, how much sunlight it is exposed to, what you clean it with, etc.

Carpet may look beautiful,but it contains lot of dust and dirt, therefore,it is advisable instead of carpet, you should go for hard surface flooring,it keeps your house dust free.Tiles and wood are the good substitute of carpets. Keep the windows closed when the wind is high and when you are not at home.Never use harsh cleaning products,always go for green cleaning,as it will be good for your health and environment.