I'm so glad you got to share one more moment with your wonderful little friends. My calico cat passed a few months ago and while she was never a lap cat I have seen her out of the corner of my eye jumping up on the bed or whatever when I'm in the other room. I know it's not just me, because my other cat sees her, too and will look at me to make sure he's not the crazy one.
My great aunt stops in to say hello every so often as well, but in a different way. I work for a real estate attorney and I was picking through an old deed of property and lo and behold, she had sold said property in 1940 to the prior owners. I have also spoken to a client on the phone who, if I didn't know better, I'd have sworn was her. She died when I was 17 but we were always very close so I take these things as her way of checking in on me.