A Knighthood for Salvador Moncada

Salvador Moncada, the 65-year-old husband of Princess Maria-Esmeralda of Belgium, received a knighthood in the Queen's New Year's Honors List. The Honduran-born pharmacologist is the director of the Wolfson Institute for Biomedical Research, University College, in London. Professor Moncada, who can now be referred to as Sir Salvador, married Princess Esmeralda in April 998. They have two children, Alexandra, who was born four months after the wedding in August 1998, and Leopold, who was born in 2001.
Sir Salvador and Princess Esmeralda reside in London. I am not sure if the princess can be styled as Princess Esmeralda, Lady Moncada, because she has a foreign title. She can be styled as Lady Moncada, however, in the UK.
Princess Alexandra is HRH Princess Alexandra, the Hon. Lady Ogilvy, but she is a British princess whose late husband was the younger son of an earl, and later knighted.
The Princess is the youngest half-sibling of King Albert II.