Are people with hyper/overly active immune systems, such as those with ms, at high risk of covid-19 like those weakened immune systems?

No one really knows: auto immune disease is an immune system that targets the cells of your own body. People are usually on immune suppression such as steroids and more advanced medications. This is what makes them more susceptible to infections. A "hyper active immune system" is not usually a well functioning immune system

Unknown: The exact answer is unknown but it is believed that people who have the most severe complications of Covid19 have "cytokine storm", an overly active immune response. I think you must be safe and assume MS is a serious risk factor and do everything possible to avoid exposure.