We have an entire roof of slate, and you will have a harder time finding a roofer who handles it. That being said, they shouldn’t have to cut (if they are standard size). Price for tile replacement can vary. It’s not cheap, but it’s cheaper to replace a few tiles than it is to re-do your whole roof. We have used Angie’s list with a lot of success. Recently we used GG Roof (or something like that), while they were pricey, they were straight forward, didn’t try to up-sell, and only bid for what we asked them to do. I find those who don’t do slate will try to convince you to remove it. So, keep looking around and it’s worth it to get an Angie’s list membership even for a month.