Ok so this is how Kiki is put into the story and how she and Inuyasha know each other. It gives the main summary of it all.
Her father married Kikyo and had Kiki. He was a priest and he knew how to work with magic potions. When Kiki was just a baby he had to go to another village because they were attacked. Before he left he sprinkled something silver on Kiki that made her age like a demon for her whole life. He left and never returned. They thought he was attacked by a demon and was killed. But he went through the well and went to Kagome's time where he met Kagome's mother. He had Kagome and Sota and then one day before he went on a business trip sprinkled something multi-colored on Kagome. That was so that when she turns 15 she will start aging like a demon. Then he got in a car crash. They never found the body. Kikyo met Inuyasha because of Kiki straying off. Then when Kikyo died Kiki was three. When she was seven she left and went out on her own. She met Tukiko and Kasumi who fell in love with Sesshomaru and had his child and then they got married. I'm going to make another story of how everyone met up again later.
I'm having trouble making the next chapter but it's summer so hopefully I will find some inspiration and write it.