The Latin inscriptions can be translated:
The most illustrious and most excellent princess Frances Duchess of Richmond and Lennox, daughter of Thomas Lord Howard of Bindon, son to the Duke of Norfolk by Elizabeth daughter of Edward, Duke of Buckingham, wife of Ludovic Stuart, Duke of Richmond and Lennox, who, ever mindful of this her dearest lord, hath to him who so well deserved it, and to herself, erected this monument. She died the 8th of October A.D. 1639.
Here lies the body of the most illustrious and most excellent prince, Ludovic, son of Esme Stuart, Duke of Lennox, grandson of John, nephew to the serene Prince King James I, Duke of Richmond and Lennox, Earl of Newcastle upon Tyne and Darnley, Chamberlain and Hereditary Admiral of Scotland, Lord High Steward of the Household, first Gentleman of the bedchamber and Privy Counsellor to his sacred Majesty King James, Knight of the Garter, Ambassador from Scotland to France; a prince born to every thing that was great and good, but gone to far better. He lived 49 years, 4 months and 17 days.
2.Samuel 3, 38: Know ye not that a prince and a great man is this day dead. 16 February. Designed the first princes of this land.
Another entry close by states:
Sacred to his memory. In this urn is enclosed the heart, while below rests the body, of the most illustrious Duke, Esme Stuart. Let him who seeks his parentage know that he inherited from his father James, first Duke of Lennox and then of Richmond and Lennox, the same title and rank, while from his mother Mary, only daughter of George, Duke of Buckingham, he derived his life and spirit, which afterwards he breathed out at Paris in the 11th year of his age on 14 day of the month of August, year of man's salvation 166[0].
This is a vault for multiple burials.
Esme Stuart, brother of Ludovic, second son of Esme and Catherine, succeeded him as Duke but died six months later of the spotted fever and was buried on 6th August 1624. His daughter Margaret was buried in 1618 in St Edmund's chapel in the Abbey. His daughter Frances was born in 1617 and married Jerome Weston, later 2nd Earl of Portland and was buried, as the Countess Dowager of Portland, in the vault on 17th March 1694.
James Stuart, Duke of Richmond and Lennox, son of Esme by his wife Catherine (Clifton), was born 6th April 1612 and died 30th March 1655. The King was his guardian and later on he fought at Naseby. He married in 1637 Mary, daughter of George Villiers and widow of Charles Herbert. After James' death she married Colonel Thomas Howard and was buried on 28th November 1685.
Charles, Lord Darnley, son of James was buried 13th October 1640.
Charles Stuart, Duke of Richmond and Lennox, was a cousin of Esme (died 1660) and was born in 1639 a son of George Stuart and Katherine (Howard). His first wife was widow Elizabeth Cavendish who was buried on 29th April 1661, his second wife was widow Margaret Lewis who was buried on 6th January 1667 and his third was Frances Teresa. He drowned while in Denmark in December 1672 and was buried in the Abbey 20th September 1673.
His title of duke of Richmond and Lennox became extinct but was later conferred by Charles II on Charles, his illegitimate child by the Duchess of Portsmouth. This Duke was buried in the vault in 1723 but was later removed to Chichester Cathedral.
https://www.westminster-abbey.org/
Mary Stewart, Duchess of Richmond and Duchess of Lennox (1622–1685), formerly Lady Mary Villiers, was the daughter of the George Villiers, 1st Duke of Buckingham and Katherine Manners, 19th Baroness de Ros.
On 8 January 1634, at the age of 12, she married the 15-year-old Charles, Lord Herbert, eldest son of the 4th Earl of Pembroke and 1st Earl of Montgomery, but was widowed in 1635 when her young husband died of smallpox or perhaps petechiae. On 3 August 1637, she married the 4th Duke of Lennox, who was created Duke of Richmond in 1641. They had two children:
Sometime before 1664, Mary married Colonel Thomas Howard (d. 1678): he was a younger brother of Charles Howard, 1st Earl of Carlisle, and is chiefly remembered for his duel in 1662 with Henry Jermyn, 1st Baron Dover.
Maureen E. Mulvihill has built a case for Mary Villiers as the author of the poems published under the pseudonym Ephelia, including Female Poems...by Ephelia (1679).
In October 1670 the duchess, with the queen, and her friend the Duchess of Buckingham decided to go to a fair near Audley End disguised as country women for a "merry frolic", dressed in red petticoats and waistcoats. The costumes were outlandish rather than convincing, and they began to draw a crowd, when they tried to buy stockings and gloves their speech was also conspicuous. A member of the crowd recognised the queen from a dinner she had attended. The party returned followed by as many people at the fair as had horses.