Is there independent research that provides effectiveness of health
care and nutrition products from MLM companies, such as Isagenix,
Nikken, and Nu Skin's nutritional line?  If so, which of these three
have more effective products with legitimate research to back it?

Is there a list of ingredients on the package of these multi level
marketing firms products?

Your more likely to find independent research on oatmeal, and soy bean oil
than trade names.

They are very effective at separating people from their hard earned money.

There was an independent study commissioned by the Canadian
goverernment covering over 300 nutritonal products.

You can get a copy from here: 
http://www.comparativeguide.com/guides/adultguide.html