In several months, certainly after the Queen returns to Buckingham Palace, after spending some quiet time at Balmoral, Prince George of Cambridge will be dressed in the new royal christening gown (first worn by Lord Severn) and be received into the Church of England. The ceremony will most likely be conducted by the Archbishop of Canterbury.
George's great-grandmother is the Supreme Governor of the Church of England. One day, in about 50-60 years, George will be the sovereign, and will take his religious obligations seriously.
The selection of godparents will be very important. The Church of England has a primer on godparents.
One does not select godparents on the basis of friendship or because you are close to your sister.
Baby George may have 4 or more godparents. The godparents will more likely come from William's side of the family. There is no doubt that William will seek and receive advice from his father and his grandmother.
I do not think that Prince Harry nor Pippa Middleton will be on the list. Harry and William are very close as are Catherine and Pippa. Being a loving uncle and aunt is not the same thing as being a good godparent.
They have other roles to play in the life of Prince George. The Duke and Duchess of Cambridge won't be snubbing their siblings, although the tabloids will say they are.
Here are my candidates:
James Ogilvy, son of Princess Alexandra (William's godmother.) He met his wife, Julia, when they were both students as St. Andrews', and their home outside Edinburgh, was a bolt hole for Prince William during his time at university. James was a mentor to Prince William.
Alexandra "Tiggy" Legge-Bourke Pettifer. Tiggy, whose mother was once one of Princess Anne's ladies-in-waiting, worked for the Prince of Wales in a number of positions, including his personal assistant, nanny and companion to Princes William and Harry. The two princes remain close to Tiggy. Harry is godfather to Tiggy's elder son, Fred, and William is the younger son, Tom's, godfather.
Tiggy and her husband maintain strong connections with the Prince of Wales and the Duchess of Cornwall.
Princess Beatrice of York. William's first cousin.
The Earl or Countess of Wessex. The future Duke and Duchess of Edinburgh.
James Middleton. Most likely, the heir to the Middletons' empire.
Lady Fellowes or Lady Sarah McCorquodale: Prince William's maternal aunts. Either would be able to tell George about his paternal grandmother.
One of the van Straubenzees, but not a van Cutsem. Roman Catholic Canon law does not permit Roman Catholics to serve as godparents at Protestant baptisms. They be Christian witnesses. The reverse also applies to Protestants, who can serve as Christian witnesses at Roman Catholic baptisms, again, according to Canon law.
Crown Prince Pavlos of the Hellenes. His father, King Constantine II, is William's godfather. Prince William's first godchild is Pavlos' son, Prince Konstantine.
A dark horse candidate might be Crown Prince Frederik of Denmark, elder son of Queen Margrethe II. Frederik is married to Tasmanian born Mary Donaldson, whose parents were born in Scotland.
Several writers have included the Earl of Ulster, son and heir of the Duke of Gloucester. Having the first name of Alexander does not mean he will be a godfather. Lord Ulster is the director of the Transnational Crisis Project, and does not undertake royal duties.