The baby’s name, will be released tomorrow.
I think the baby’s first name will be James after King James, a simple solid name like older brother George. Also it is the name of Kate’s brother.
I think the next middle name will be Philip after the Queen’s husband and Kate’s sister Philippa.
Then I think the baby will have a second middle name like his siblings. Possibilities for this:
Henry after baby’s Dad William’s brother (Harry is a nickname his official name is Harry.
Arther after King Arther.
Charles after William’s Father.
Michael after Kate’s Father.