Basically 経営する means to own/run/manage (a company) and 所有する is much broader to own, which means the subject have rights to some property (land, car, etc.).
So for a privately owned company, 経営者 = オーナー (= 所有者). For a listed company, 経営者 means CEO and オーナー means stock holders (which may be controversial).
Practically
- オーナー in such sense is used for small business like shops or restaurants. It is also possible to say things like 車のオーナー=the owner of the car.
- 代表取締役・社長 is more commonly used for CEO of a listed company (There could be difference among those, but it is less of language issue). 経営者 is more used to denote the 'top persons' of companies (private or not) in general.
事業者 is a term mostly used in the sense of company, corporate body. Its use is restricted in specific contexts (e.g. legal). For example, when a government mentions something about mobile network, 通信事業者 is used to mean telecom companies (like Docomo or KDDI in Japan).
(added) In case of restaurants, オーナー and 経営者 are both fine. 経営者 may be preferred in cases (1) they only manage a restaurant and all the cooking is done by employees. or (2) they run a restaurant chain/multiple restaurants.