The article is sound,.
With regard to item #2, cardio is a sure fire way to drop off muscle, especially if you aren't eating enough calories, but, there's more involved and that has to do with how calories are found, and utilized, with steady state, extended, cardio.
Vastly more effective for fat loss, muscle preservation, cardio threshold improving is HIIT, and without the impact injuries and imbalances of some steady state cardio, and the muscle loss.
You'll want to study up on HIIT.
Resistance training is the only exercise that will increase your metabolism (by adding muscle) as you grow older, increase your glucose tolerance (as well as increasing your insulin sensitivity), and provide you with strong bones.