I am so sorry about your recent losses. I cannot imagine how hard it must have been so close together.
It comforts me that even knowing they can never be replaced in our hearts, every time a beloved kitty goes to the Bridge, he or she can be honored by giving a loving home to a kitty that desperately needs it when it is time. You will know when the time comes. My dear Fred brought me 3 desperate kittens when he visited me on different occasions. He knew my house was getting too empty. I feel like he will always be with me, guiding me.