Creativity is technically called Creative Imagination in Aesthetics and in Art Criticism. Its most essential feature is Empathy, which is quite different from Sympathy. Empathy is the power to dissolve one's own identity and ego, and become one with the character of the work of art. As long as Ego is there, no great work of art (or science) can be created. In other words, Creative Imagination is something like Sampragyaata Samaadhi, in which Ego is dissolved but consciousness of surroundings remain. Sarjanaatmaka Kalpanaa is a small replica of Kalpa by Brahmaa Ji : artist is a little Creator, like the Brahmaa-priest in Vedic Yajna ( = Kalpa Vedaanga). The Artist Creates a new world through an abnormal type of Imagination called Creative Imagination, which is a divine blessing.
Therefore, AK and Lagna and Lagnesha must be auspicious for making the Ego saatvika. Moreover, the houses of real wisdom (4H, and its helpers : 8H and 12H) should be auspicious so that this saatvika ego remains under control of the supernatural, without whose activation Creative Imagination cannot become active.
5H is for worldly knowledge &c. In Art, the role of 5H is limited to presentation of the work in proper technical form so as to be appealing and successful in the world.
Art has two chief dimensions : Empathy and Communication. Communication of feelings is Art. Communication is different from Expression. Communication of feeling means arousal of same feeling in the spectator or reader which the artist intends. Quality of Communication depends on 5H. Quality of Empathy depends on AK and Lagna (svabhaava).
These are generalisations. In fact all houses of horoscope play their roles in Creativity and give concrete shape to the nature of the artist and to the wroks of art created during different dashaas of planets in life. Moksha Trikona (4H-8H-12H) should be auspicious for real Wisdom. Dharma Trikona must be auspicious for saatvika svabhaava due to 1H, technically sound work of art due to 5H, and ethically sound values in that work due to 9H. Kaama Trikona (3H-7H-11H) should be auspicious for desires to be without ego-centricism and strictly under control of Creative Imagination. And Artha Trikona should be auspicious for keeping worldly lusts for money &c under control. During moments of Creativity, all twelve houses of horoscope must be auspicious, or at least the foul planets must be weak and inactive. During those rare moments, the artist is quite different from his worldly Self and from common mortals : the Creative Artist (and real scientists like Newton or Einstein) is a small incarnation of gods during those special moments of Creativity. A weak and largely Unconscious mortal transcends the borders of his/her limitations and his/her consciousness merges with the Cosmic Consciousness to some extent during rare feats of Creative Imagination due to 8H and 4H, which later gets transformed into real work due to 5H.