Slytherin :
Ghost : the bloody baron
Artefact : Salazar slytherins locket
Colour : green and silver

Gryfindor :
Ghost : sir Nicholas demimsey porpington ( read the books for proof)
Artefact : Godrik Gryfindors sword
Colour : red and gold

Hufflepuff :
Ghost : the fat friar
Artefact : Helga Hufflepuffs cup
Colours : yellow and black

Ravenclaw :
Ghost : the grey lady
Artefact : Rowena Ravenclaw
Colours : blue and silver