Estella looks beautiful and desirable, but she has been conditioned by Miss Havisham to be cold and heartless. Magwitch appears to be a terrible criminal, capable of anything including murder, but underneath he is good-hearted, industrious, and generous. Joe Gargary appears to be an ignorant and stupid man who is usually covered with dirt, but underneath he is a real gentleman and a noble person. Miss Havisham acts like an arrogant and aristocratic lady, but she is afraid of being hurt and is in hiding from the world.
It is hard to see which minor characters act as foils to all four of these major characters. Pip's cruel sister might be said to act as a foil to her husband Joe. Magwitch's bitter enemy, the other convict he recaptured on the marshes, might be considered a foil to Magwitch. I suppose the girl that Herbert Pocket is in love with and eventually marries could be a foil to the cold Estella. Miss Havisham spends so much of her time alone that it is hard to see what minor character could be a foil to her.