Have you had a lot of rain, or do you use frequent overhead watering? It's hard to tell for sure from pics, but it might be botrytis. Looking at the yellowing lower leaves. They need good air cirulation. Someone else might have a different idea, but that was my first thought.

we were having a bit of rain there for a couple of weeks. Yes. I kind of was wondering if maybe it had something to do with that or mud splashing up from underneath.

Not sure about the lilly but for your hosta you can take egg shells and spread them around the plant to keep the slugs away.