You are a good person for taking care of those feral kitties! They are lucky to have you!!
You are so correct about the hanging around low shurbs. On both sides of my front door they stay. Its as if they are guarding it. When other cats come for some food, they all appear.... mumbling /growling under their breath. I am close at touching another of the 4. He can't resist the feather stick. And when I put my hand out to touch... he places his paw on my hand. He is the only one that has gone in the house but came out quite quickly. I was hoping they would use it when it rained... but, they would rather get wet. Well... it is there, should they need it.
I have even sprinkled catnip from my front door to the back yard where the house is... hoping they would follow the smell. But, they never leave the front.
The only thing I've seen in my yard is a possum... and I'm NOT fond of them *shakes head*. I need to unleash my indoor kitty... as he used to jump on top of possums when he was an outdoor feral kitty.