Four cats that are brothers do not look exactly alike. They do look different.
Humans like different types of cats, one like red ones, others tigerstriped the third one white.....
Psychological it is better to have different looking so I as a person can side more with one than the other.
White cats have either yellow eyes, blue eyes or oddeyes. Again something which would give them much more of a personality than the same colour as a t-shirt. Just absurd.
Correct the teeth too as Monteray Jack said.