Cecily Anne Helen Victoria or Philipp Andrew Albert Christopher
Little Viscount:
For Louise they only used traditional names, already used for other princess or queens during the last few generations. So i think they will only use tradtional names again.
For a boy it could be Philipp, Andrew, George, Albert, Arthur or Edward. And maybe Christopher because of Sophie's Dad.
i think it will either be a
Philipp Andrew Albert Christopher or
Andrew George Edward Christopher.
Little Lady:
names used for princesses in the last generations:
Victoria, Alice, Helena, Louise, Beatrice, Maud and Mary
names used for ancestors (grandmothers, greatgrandmothers etc.) of the baby: Elizabeth, Mary, Alice, Olga, Victoria, Cecilia, Alexandra.
names of former queens. Elizabeth I+II, Mary I + II, Anne and Victoria.
Elizabeth, Mary, Louise and Alice are used for the elder daughter. Beatrice is the cousin and Princess Alexandra, Lady Ogilvy is also still around, so i think they will not use one of this names.
So only Victoria, Helena, Maud, Olga, Cecilia and Anne are left. Maud and Olga are maybe to oldfashioned.
I think
Helena Victoria Cecilia Mary is a possible name.
Or (which i like better)
Cecily Anne Helen Victoria.
Cecily is close to Cecilia (by the way Cecilia was the name of the mother of Elizabeth, the queen mother). Cecily was also the name of Cecily Neville, Duchess of York and mother of two Kings- so it's royal enough