I wonder if have is also considered as a copular verb beside be. The reason is that have can sometimes be used as state of being like be. For example, we say "he has a degree in linguistics", which is the same as "he is a linguistics graduate".
It's important to understand what a copular is. Downing & Locke (2006) gives the following definition:
Copular verbs, a type of intransitive, require a Subject Complement. Only verbs capable of being used as copulas can be used in this way.
Copular verbs do not take direct objects as other lexical transitive verbs do, such as HAVE. BE, for example, takes a Subject Complement as in:
- He is a good person
- He is good
Note that Objects must be noun phrases, which is not the case in #2.* Gerund-participial clauses can function as an object but only when it's the predicand of a predicative complement as in "I find talking to Max rather stressful".
*'A good person' is not an object either; it cannot be promoted to subject in the passive clause.