Kirsten if you look at semi-feral cats e.g. in Greek monasteries you will see that they live in losely connected groups. You can see that moms help each other with the babies and that thhey love to be where others are -though not to close,

Therefore I think it is important that both cats have their spaces where they can retire -and you can't be sure that they will be really good friends but I am sure they prefer not to be alone.