I would like to know if usage of indefinite articles in the following sentence is appropriate or if there should be definite articles in their place.
1) A leopard cub Leo and a tiger cub called Tig experience various fascinating adventures and learn how to help each other and be kind.
I believe it appropriate since there is definitely many cubs in the world and we mention them for the first time, but maybe I'm mistaken and presence of proper name changes the situation? Couple of other examples:
2) An animated series about the adventures of two unfailing friends, a brown bear Innokenty and a polar bear named White Cloud.
3) Dr. Ryan Stone goes on her first space mission under the command of an experienced astronaut Matt Kowalski.
4) A popular country musician whose career is rapidly going downhill falls in love with an unknown, but very talented singer Ally.
And the opposite case:
5) Psychoanalyst Ben Sobol gets a really hard case, the New York mafia godfather suffering from depression.
I believe that since mafia godfather is a singular position, the indefinite article would be appropriate. Is it correct?