According to the requirements, I have added a lot of space for your beautiful collection of plants, you can keep your existing planter box in the corners, the projection area has been converted to planter box, so that you can add larger plants if needed and to get a framed view of the fortress. On one of the side walls I have given a tree-shaped play area for your kittens so that they also have a view of the fortress . I have added blue and white printed tiles( Moroccan style) but that's optional, your existing floor is just fine. Added a seating area facing directly to your fortress where you can have a drink facing it and also additional roof is provided, so that you can use it at all time of the day, and will let you enjoy the rain as well, lastly I have added some lights to make make it usable at the nights and adds mood to the surroundings.