I was working this out on the back of a fag packet earlier (well a condom wrapper but hey ho...)
The Queen
Prince Charles
Cammilla Parker Bowles
Prince Edward
Sophie Rhys Jones
Prince Andrew
Sarah Ferguson? (Moral support for Beatrice and Eugine)
Princess Anne
Timothy Lawrence
Prince Harry
Prince William
Princess Kate
Princess Eugine
Jack Brooksbank
Princess Beatrice
Edoardo Mapelli Mozi
Zara Tindall
Mike Tindall
Peter Philips
Autumn Philips
Lady Louise Mountbatten Windsor
James, Viscount Severn
That leaves 8 spare places, which theoretically could be taken by his eight grandchildren but given how young they all are this seems highly unlikely. An exception to this might be Prince George, given his likelihood of being King George one day.
You can probably fill out the rest of the births with Queens cousins a few royal staff, given all of Philip's siblings predeceased him. .