I don’t think the example cited for an Anniversary fact is going to work for a Census fact. The reason is that the example for the Anniversary fact is using the [Spouse] variable to access the surname of the husband to get the married name of the wife. The [Spouse] variable is available for couple facts like Marriage, Divorce, and Anniversary but not for individual facts like Birth, Death, and Census.
Well, I’m assuming you are using the individual Census fact. You might get it to work for the couple Census fact (also known as the family Census fact). But the couple Census fact doesn’t seem applicable to a mother and daughter combination. I may not be showing sufficient imagination in getting this to work, but I can’t quite see how to make it work. Genealogy tends to work primarily with a woman’s birth name rather than her married name. You can assign a woman’s married name as an Alternate Name in RM, but I don’t think you can then get at the Alternate Name in a sentence template.
If all else fails, you can always customize a sentence for a particular instance of a fact for a particular person. Doing it that way, you don’t have to use variables. You can just write the sentence the way you want it to look. That will always work.