Would K-97 work for a Kolsch? If not, what dry yeast wold you suggest?
No, not great in my experience.
It sounds crazy, but I really really like Lallemand London ESB Ale. Fermented cool, it turned out very clean for me. Its drawback might be its attenuation, which in my experience was about 71% but others have reported it in the upper 60s. So if you want to try it, consider mashing for a very long time, like overnight, to keep the enzymes working for a good long time, in the hopes that this will keep the beer dry like a Kolsch should be.
Dang....... now I really want to try this! I'm making a schwarbier this week, I'll split the batch and give it a shot! I'm pretty sure I still have some London left, will have to check. If I do try it, I'll try to remember to report back with results, or send me a reminder.