Ok, there's a lot of confusion here but some good leads. My thoughts as follows:
Joseph Watson b1740ish was farming in the Swanland area 1779, when he was on the list of rentals. The number 10 is not his age but rather the rentable value of the land. In other words, the biggest Watson landowner in Swanland in 1779 was John Watson (perhaps born 1719), followed by Samuel, Thomas, Joseph, William, Henry. Could that mean that John was the oldest and possibly the father of Joseph? If Joseph was born ±1740, he would have been 39 in 1779 and John would have been 60.
We have already established that Joseph's sons were William (1768-1809), John (1778-?) and Joseph (1784-1855). William was farming at West Ella Grange when he died in 1809; if the William farming there in 1841 was his son, he would have been born in 1801 and only 8 when his father died. So he could not have taken over the farm at that age. Perhaps someone else stepped in (grandfather Joseph or uncle John?) and William took over in 1830 after leaving Kirk Ella (see below).
Most of the children of Joseph b1884 were born at Little Weigton so I think it's safe to assume that he's the farmer listed there in Baines' 1823. The first of his children born at Kirk Ella Grange was Rebecca, born 31 Oct 1830. So I think it's safe to assume that Joseph took over the lease at Kirk Ella Grange ±1830 (?taken over from William Watson, but which one?) and was there until he died in 1855, when it passed to his son Joseph.
So perhaps the line run like this:
Henry, Overseer of the Highways of Swanland in 1695, died 1723 - leaving 5 sons: Henry, John, William, Thomas, Samuel
John b±1690, farmer at Swanland
John b1719
Joseph b±1740
Joseph b1784
Sounds plausable - but we need proof