Spirit Blossom is Ionian event that happens once a year (I think) where Trees called Spirit Blossom Trees Bloom and their petals that can consist Spirits of those who died get harvested by those who wanna talk with someone who died. They make tee of those petals, allowing them to make contact with spirit that was captured in a petal. Now how spirits end up in petal is unknown, so there is a myth that when someone dies, their soul ends up in spirit world where they can follow fox that will lead them to Spirit Blossom tree in spirit realm where they can rest in peace and be able to contact with living world thru already explained, or get tempted by some other spirits and get lost forever in their own negative emotions. So they made all of that in festival as a celebration of life and death in general, with their myths and stories. So this Kindred is how Ionians see Kindred, since Kindred is death it self. Spirit Blossom Thresh is not Thresh but Ionias Spirit of Obsession. Spirit Blossom Yasuo and Yone, are not Yasuo and Yone, but are two brothers from Ionians folklore story who killed each other on battlefield over two swords Spirit of Obsession transferred from Spirit World To Mortals World. Spirit Blossom Temmo is Spirit of Pranks (or something like that). Cass is spirit of Temptation, Spirit Blossom Vayne is folklore Story Deamon Hunter, Spirit Blossom Lilia is spirit of dreams, since Runterras Lilia can look at others peoples dreams and probably appear in them, they present her as Spirit and Spirit Blossom Ahri is spirit of Fox i already explained. That's lore based explanation.
