The LDS (IGI) records have been found to be unreliable. In some surnames, there are so many errors that you pretty much have to throw out all their stuff. The researchers were LDS members who had a goal of baptizing at least 100 people, alive or dead, so accuracy was either not the top priority or it was just plain faulty research, sometimes by heresay or guess work. So, you have to find sources and double check their work.
As for Darling Whelpley, he and his wife Abigail and their sizable family did sail for New Brunswick in 1783. Both Darling and Abigail died in St. John, New Brunswick, Darling in 1813 and Abigail not too long after him.
I have no record of any Abigail who had married a Whelpley then marrying a Kelly/Kelley. Are you sure it was Darling or should I say a Darling Whelpley, who was married to Abigail? There was a Darling Whelpley, son of Jonathan III, who was born 1768-1772 about whom we have little info. The 1806 year could work as the date of his widow's second marriage, if he died rather young. Was there a source for the LDS entry?