2,
If I keep my surname Zhang, but the first word in my name is "Li", this method is certainly feasible and the regulations allow it. I am a geomantic layout named after Zhouyi, and it is ok to take meaning by name. Li is both a first name and a mother's surname, killing two birds with one stone.
3. Is Zhang Liren X "reasonable (in line with current social and historical customs)? Of course, there have always been four-character names, especially for ethnic minorities, which is also a good combination.
4. You can name it like this: Zhang X, or X, and the word Ren is placed before or after the name, depending on where your family tree is ranked. Since it is named after genealogy, it should be named according to the rules of genealogy. China's inheritance is that the child takes the father's surname (unless the husband and wife later agree to change the mother's surname or the divorced child's surname). Putting the mother's surname in the child's name is nothing more than the existence of the mother's surname, which does not mean that it is the child's name.
As for the name change in adulthood, there are many now, because the parents of these two generations live in different ages. Generally, children will not choose their names according to their eight characters until they think their names are different, but this will cause great inconvenience to their work and life. It is best to choose a good name according to their eight characters when children are born.
Are you satisfied with this answer?