I would get rid of the day lillies if they are in her yard. I found this:
Easter Lilies:
Some members of the Lilly family of plants can result in serious illness in cats. Specifically, Easter Lilies, tiger lilies, Japanese show lilies, rubrum lilies, many lily hybrids and
day lilies have been known to cause kidney failure.
Toxic Foods and Plants for Dogs
The pine bark mulch is considered non-toxic. The thing is that they can choke on it and I'm certain it wouldn't be healthy for their intestines.