I think Korg visiting the bath will take place after Rose's visit. Her visit happened to me during around 14 when I came back to home. And for Korg's visit to the bath, I was only able to trigger it after giving him some massage which I think can only be triggered when having muscle ointment. And I think we need to do it more than once and his visit would only happen at night. Just be sure to keep talking to him and you'll be able to propose visiting the bath.
For the problem about Ste's house, it's just that hard to find. I repeatedly inspect the area to find it to a point I almost gave up. I found it in the end. I think we need high perception. I don't really know honestly cuz I already built perception since beginning. And I used focus tea to improve my perception too because I thought I needed it.