The Falconhurst Noble Family

The current leader of Falconhurst is Harden Sunroot. His full list of titles are: Duke of Falconburough, Earl of Whitesea.
The correct way to refer to Harden Sunroot is: 'Your Grace' or 'Duke' Harden.
Harden is a widower. He was married to Clementine Sunroot, who was the Baroness of Yellowseed.
He has only one child.
His son is Nigel Sunroot, who's Viscount of Blue Fields. He is married to Blaine Sunroot, Viscount Consort of Blue Fields.
Nigel has two children from a previous relationship. They were unmarried but Nigel initially put the children in the line of succession.

• Hunter Sunroot, current Baron of Yellowseed
• Desmond Sunroot

You would refer these as Lord [first name].
Nigel and Blaine have one adopted daughter.
Her name is Brooke Sunroot. You would refer to her as Lady Brooke.
There is debate as to whether the title of Duke of Falconburough should be passed to Hunter or Brooke when the time comes. Hunter Sunroot is married to Eden Hawkweaver. Together they have a daughter. Her name is Madeline Sunroot.

Harden Sunroot