Your box is pretty mixed, as expected of most early-mid game boxes. I'd assume that most people would agree with me in saying that Christmas Sakuya is the best card in your box, however, her usefulness derives from your ability to combo four colors consistently. If you feel you can use her, you could make a team that's something like:

[ Astral Bell Kirin Princess, Sakuya ] [ Brilliant Sun Deity, Apollo ] [ Holy Rites Mistress, Echidna ] [ Dimensional Travelers, Aemo & Mootie ] [ Empty/Wildcard ] [ Astral Bell Kirin Princess, Sakuya ]

The empty slot can be filled with any healer card. Ideally, later on you change Apollo into Awoken Apollo to hit the healer type, and add Light Izanami somewhere into the team. I put Aemo & Mootie on there as a safety net for important floors in case you need extra move time. In the empty slot, you could put Angel/Archangel or Mystic Light Knight, both farmable.

Also IAP meaps in-app purchase.