I had the same thought about Cormoran and Robin initially but I’ve changed my mind since Jo tweeted those tarot cards. The one that basically says “tell the other how you feel, they may feel the same, etc” made me very, very happy. My guess is there will be some tension and they’ll both acknowledge their feelings to themselves and (probably at the end) have a talk. A really good talk where Strike takes his own advice of “We’ve got to be honest with each other…”
I have the idea that Charlotte will end up loving her children and being a good mother. I know she’s a horrible person, kind of, but people do change when they become parents – I know I did. So I think she will find happiness in her kids, much to her own surprise!