Ants are usually a symptom of a problem, not the cause. They form a symbiotic relationship with many types of insects (aphids and some scales to name two) by "protecting" or "farming" them . In return for caring for these pests, ants harvest the sticky secretions, or honeydew, from them.
I noticed on one of the photos what looks like a sticky substance? My feeling is that the ants are just being opportunistic and, once the other pests are eradicated, the ants will move on (no one to herd and milk, if you will). I cannot see the tiny black insects but they may very well be black aphids.
The red lily beetle is only red when it is an adult (it kind of looks like a ladybug). Prior to adulthood, it goes through a nymph stage (baby stage) where it looks like a tiny "slug-shaped" critter covered in its own fecal matter. I am pretty sure that is what is in your first photos. You won't see a red beetle for another few weeks until this batch of babies transform themselves but, hopefully, you will be rid of them by then and not have to worry.
