Kylo had a major scene with Han in TFA. As for Leia, I’m giving them a pass because no one expected Carrie Fisher to pass away and they made plans for IX to be her focus like TFA was for Han and TLJ was for Luke.
Carry passing away was a terrible thing. And I don’t want to take that away, but we have to deal with reality now. And I’m actually glad that Leia isn’t going to be in IX as I don’t think Carry could act anymore. Plus she didn’t look like an old lady Leia that I would have wanted to see. I think Carry’s stuff in the ST is just one of the worst things about them.