The 1987 Hallmark movie makes Mary and Colin NOT cousins and she ends up with him (the older him is played by Colin Firth). Dickon is rather unnecessarily killed off.
And the 1993 movie implies a crush between Mary and Dickon that makes Colin jealous. The issue is never addressed in the movie. I suspect it was there to remind the reader of Mary's part in the story.
Me? I put Colin and Dickon together!
Mellors of Lady Chatterley's Lover and Scudder of Forester's Maurice were based on a working-class man, George Merrill, who lived (without anyone going to jail) with Edward Carpenter (Carpenter was capable of supporting a household where people didn't end up in jail). Merrill was ostensibly his servant--the intimate relationship was acknowledged by friends and they were buried side-by-side.In sum, Carpenter embodied the kind of utopian philosophy that 10-year-old Colin spouts off while Merrill embodied the (literally) down-to-earth behavior that Dickon practices. They are decent representations of Carpenter and Merrill. (Both Mary and Colin are enamored of Dickon; in the book, it never crosses the line out of childish hero worship.)
Two snags: Colin is not really the sit still type. I can't picture him voluntarily moving back to Misselthwaite Manor in his later years. He strikes me as a city-university lad. Or an explorer. Or an anthropologist.
And Dickon loves Yorkshire. He is the Andy Griffin of his home soil. He wouldn't want to leave.
In addition, for all Lawrence's praise of men of the soil (Forester was somewhat more insightful), people of Dickon's class could be far more conservative than people of Colin's class. Colin might find the Bohemians kind of staid (seriously--he's waaay out there). But he would get to know them. Dickon, on the other hand, has a large loving family that he wouldn't want to embarrass.I have Dickon and Colin find a way to stay together in my Thatcher-Damien heaven or heavens: in my Thatcher-Damien fan-fiction's afterlife, there are all kinds of heavens for all kinds of people. Dickon-Colin's heaven is a kind of Victorian/Edwardian steampunk city that sits next door to a Yorkshire-type countryside.
As for Mary, I don't see why she needs to get together with anyone. I see her as a kind of Nellie Bly, heading out to explore the world and collect seeds from different countries. Why not?!

