Not everything you find on the Internet is authentic or genuine, especially social networking sites like Facebook or Twitter where people take all liberty in writing English. The perfect example is the one that you quoted in your sentence.
As StoneyB says, the idiomatic sentence will be...
"...and each of the sons/every one of the sons has a sister. How many members are there in the family?"
To confirm the usage of words, I suggest you searching for the news articles on the Internet or COCA
"Own" is transitive, and takes a Direct Object:
"Belong" is intransitive, and takes an Indirect Object (or none at all):
A belongs to B
C does not belong here
As for your examples: in Example 1, neither the question nor the answer is in correct form. They should be;
Q: Does this property belong to my father?
A: Yes, this property belongs to yout father.
(Neither of these is in passive voice. They can't be, because "belong" is intransitive.)
in Example 2, both the question and the answer are formed correctly. Both are in passive voice, which is possible because "own" is transitive.
Your last query, about whether "belong" and "own" can be used as stative verbs, has nothing to do with your examples or with the title of your Question.
If I understand correctly, both "own" and "belong" are stative verbs, no matter how you use them, but the stative/active distinction is independent of the transitive/ intransitive distinction.
Best Answer
We call it an Infinitival Relative Clause (hereafter, IRC). Or if you don't want to analyze it as a relative clause, you can just call it a post-modifing infinitival clause. This IRC is so flexible that it can occur with either a passive voice or an active voice. This is explained by Biber et al. in Longman Student Grammar of Spoken and Written English.
The e-mail address of the Facebook account to delete
(This is in the active voice. The object of the verb delete is missing, so this IRC has a non-subject gap.)
The e-mail address of the Facebook account to be deleted
(This is in the passive voice. The subject of the infinitival clause is missing, so this IRC has a subject gap.)