Since all of them know their names, if you are looking for someone in the house, or just wonder where they've gotten themselves off to, or just want to have a little one-on-one love time... You sing their song. My husband and I both did this before we got married, then found the commonality once we blended our pet-kids. They don't care if you cannot carry a tune, they just love that you have a song "just for them." This was Buddy's song.... (he was a orange/red tabby):
Budster
Budster Lobster
Lots of kids
love Budster Lobster
Fat kids
Skinny kids
(hum if you forget the words, he doesn't care)
Even kids with Chicken Pox!
Love Lobster
Budster Lobster
The cat kids love to love!