One benefit of multiline raw string is that you can directly copy/paste a block of characters between the program and its source. Unless there are very sophisticated IDE support this proposal does not work fine in this sense.
As I understand, only children of father's brothers can be prefixed with 堂, because they have the same last name and are traditionally considered to be in the same house. All others, including children of father's sisters, are all prefixed with 表.