You will be surprised when you start hatching keets. I had pieds that threw, pied, pearl and whites. There are so many possibilities of what their parents, grandparents, great granparents, etc., etc, etc, have in them, theres no telling what you will get.
I could be wrong, but I think you will most likely end up with all pearl keets - unless there are some other color genes in the pearl males' background. Pearl gray is a dominant color, so the resulting first generation keets should look like pearls but will also carry the slate color in their genetic makeup that could come out in later generations.