Yesterday I watched the film "The Light bBetween the oOceans" with Michael Fassbender.

I liked thise film.

The story is about a young married couple - Tom and Isabella, whicho lead secluded lives on an island.

Tom works as a lighthouse keeper.

The happiness of the lovers is gloomovershadowed by the fact that Isabella had two miscarriages.

"the lovers" works here, but I think "the couple" would sound more natural than "the lovers" in this context.

She was depressed and hasd been lying down for a long time near the graves of her children while the boat withen a boat carrying a dead man and a little child came towashed ashore on the island.

Since it sounds like the man is dead and the child is too young to be steering the boat, it would probably be best to use "washed ashore" because it gives the impression that the boat is drifting in the water on its own and was brought to the island by the waves rather than someone steering it.

Yesterday I watched the film "The Light bBetween the oOceans" with Michael Fassbender.

The context here makes it clear that you are talking about a movie, and that Michael Fassbender is an actor in the film. And it is aided by the fact that Michael Fassbender is pretty well known. So this is perfectly valid phrasing. But out of context, it could have the grammatical meaning that you sat down and watched the film with a person named Michael Fassbender.

The story is about a young married couple - Tom and Isabella, whicho lead secluded lives on an island.

Not exactly sure what you are saying. They live on an island which might be close to other places and easy to get to, and they live a very private life or there are not many people around - "lead secluded lives on an island". They live normal lives on an island, but the island is far away from other places or hard to get to - "who live on a secluded island"

Tom works as a lighthouse keeper.

The happiness of the lovers is gloomdarkened by the fact that Isabella had two miscarriages.

I think it sounds more natural to say "The happiness of the couple is darkened by the fact". Lovers sounds just a little too poetic for this type of description.

She was depressed and hasd been lying down for a long time near the graves of her children while theen a boat with a dead man and a little child came toin it arrived at the island.

I think the part about the man and child is a little ambiguous, but I think it's just a feature of English which doesn't make it easy to elegantly say it clearly. Is it a dead man and an alive child? Or a dead man and a dead child? I think it's ok though. I think I would use "arrived at the island" instead of "came to". To me, came to indicates that there is some sort of knowledge of the intention or purpose of coming to the island. Yet a little child and dead man don't seem like people who can demonstrate a clear intention to purposefully have a reason for travel. "Arrive at" just emphasizes the fact that there was something that wasn't there, then it was at this place, without worrying about what the initial intention of the journey was. In addition, the other suggestion of using "washed up" could work too, since washed up implies that the boat was drifting in the water with no one directing it and it came to shore by chance. And it seems likely the little child or a dead man could not steer the boat. Arrived at can still have a little connotation of being the end of a purposeful journey.

Yesterday I watched the film "The Light between the oceans" withstarring Michael Fassbender.

I liked thise film.

The story is about a young married couple - Tom and Isabella, which secluded lives ono live on a secludes island.

Tom works as a lighthouse keeper.

The happiness of the lovers is gloomdampened by the fact that Isabella had two miscarriages.

She was depressed and hasd been lying down for a long time near the graves of her children while theen a boat with a dead man and a little child came towashed up on the island.