I've managed to piece together some information about the Wickede family.
Eliza Frederica Wickede was the second daughter of Major Frederick von Wickede (1774-12 Oct 1822). Frederick's eldest daughter was Augusta Maria Wickede, who married at Tranquebar, India 31 July 1826 Captain Francis Plowden. Frederick's third daughter was Grace Wickede, who married at Quilon 20 November 1830 William Strickland, of the 6th N.I.
Frederick had a mistress called Christine Neuss who gave birth to a daughter called Carolina Lavinia Wickede on 9 August 1813 (baptised at Calcutta 22 March 1814). Carolina married at Calcutta 3 September 1830 Frederick William Johns (born circa 1807).
Frederick von Wickede was the son of Friedrich Bernhard von Wickede, a writer and silhouette cutter, who is famous enough to have his own german wikipedia page:http://de.wikipedia.org/wiki/Friedrich_Bernhard_von_Wickede
Frederick was the only son of Friedrich Bernhard's first marriage to Magdalena Augusta Dorothea Vanselow (1751-1786).
The von Wickede family originated in Dortmund and served as Mayors of Lubeck for 400 years:http://de.wikipedia.org/wiki/Wickede_(Adelsgeschlecht