I have two questions:
My lilies are spread apart and I would like to know what to plant around and under them?
Also I have those annoying red beetles which I try to pick off daily. I used to use Neem oil but it is no longer available. Any other options?
As far as your Red Beetles are concerned, this question has already been asked and answered by my peers so I have included the link for your perusal, see below:
Regarding your Tiger Lilies or Lilium lancefolium:
Depending on the growing conditions of your Lily bed, there are literally hundreds of options for plants to add around your Lilies. I have added a link with a varied list of plants with similar growing requirements to your Lilies:
For planting options underneath your Lilies: