Can demographics group consumers by needs that differ by gender, household size, family status, income, occupation,education ,religion, race, nationality, or social class?
If I understand your question correctly, the answer is “no.” In the scenario that you present in your question, the individuals in the consumer groups have different demographic characteristics. The only thing that members of a group appear to have in common is their needs. "Consumer Needs" is not a demographic characteristic. Therefore, demographics cannot group these consumers.
In order to understand this, let us first look at what “demographics” are. Demographics can be defined as data that gives us information about the characteristics of a given population. These characteristics have to do with the people’s attributes, not their behavior. All of the things that you mention in your question are demographic attributes. However, people’s behavior is not a demographic attribute. For example, we would not say that people who subscribe to Netflix constitute a demographic group. Subscribing to Netflix is a behavior rather than an attribute.
In your question, you tell us that the members of the consumer groups differ with regard to gender, household size, family status, income, occupation, education ,religion, race, nationality, or social class. This means that their behavior is not connected to any of these factors. For example, it implies that white people and black people are equally likely to belong to one of these groups as are poorer people and richer people. What this appears to mean is that your consumer groups are only united by their needs. They have nothing in common (statistically speaking) other than the fact that they have some particular consumer needs. Therefore, they cannot be separated into groups based on their demographics.