3 Open Questions about Thomas and Friends

As I watch Thomas and Friends, I am struck with questions which there seem to be no answers to. Actually, I have LOTS of questions, but these are the 3 most bothersome ones to me.

• Why do all engines, but not all trucks, cars, planes, and boats have faces? Shouldn't cars, trucks, planes, and boats all be characters too? For instance, The Fat Controller, Sir Topham Hatt, has a blue car that is not sentient, but his red rail car/track inspection vehicle, Winston, is. Butch the Tow Truck/Heavy Recovery Unit and Bertie the Bus are sentient, but the vehicles in Blue Mountain Mystery were not. Jeremy the Jet Plane is sentient, but the first planes to land on the Island of Sodor in Calling All Engines are not. All the narrow gauge coaches are sentient  but the Express coaches appear not to be in the animated series.
• Not all sentient vehicles have face. This is very disturbing. Toby the Steam Tram has a coach named Henrietta (that my son thinks looks like a caboose) but she has no face! If one argues that the Express Coaches are sentient from the books, well they have no faces either!
• Why are some engines numbered, bit others are not? Most of the steam engines are numbered, but Rosie and Stanley are not. Very few of the Diesels are numbered. The numbers are pointless if all engines do not have them? And shouldn't numbers change when engines relocate to Sodor (i.e. Victor, Salty, Belle et al)?