Actually Heathcliff does not name his son. His wife, Isabella, leaves Heathcliff before the baby she is carrying is born and goes into hiding. She names the boy Linton after her maiden name, her family's name.
The name is interesting because it, made of the names of both parents, shows his potential to take to different paths. Primarily raised by his brooding and boorish father, Linton takes on the worst of the Heathcliff qualities and becomes a spiteful man. Had Edgar Linton, his uncle, been able to raise him, he may have been a more pleasant and kind-hearted person.
Below is a link to a summary of Wuthering Heights that explains that Linton was born away from his father and was named by his mother. I've also included another link to a brief description of the characters.
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