Well stalkers are usually want 1. attention, 2. feel to be in control/power. If they don't get these they can escalate further or just get bored and stop (and look for other entertainment, maybe someone else who reacts easier).
The first one doesn't sound too bad, and relatively easy to ignore. The second is more problematic because he seeks personal contact.
I think you should ignore as much stuff as possible, and don't get bothered by it. You might wanna think of it as some kind of weird entertainment, and say to yourself: "this guy is here again, let's see how he makes fool of himself this time". You also might wanna discuss this with family and friends yes, you getting more isolated from friends as you said makes it harder sadly
, but be aware that you should tell it in a way that doesn't make you look like a crazy person. Plus the stalkers might approach them and stalk them too, so a kind warning also due to them, to be careful and stay safe.
You should be mindful about locking your home and keep your belongings safe. And since it is annoying you also should learn to relax. Especially in the evenings, so you can have a good night sleep, because that can influence your everyday performance tremendously.
Make your life less predictable for them. Take alternative routs, do stuff in non-regular times.
You should check local laws, about stalking (harassment?), libel (since they spread doodoo, it could fall into this category), and self-defense, so you know what can you do, and when can you turn to law-enforcement. You might wanna ask a lawyer too. If it is possible, it is legal, get a pepper spray in case they turn violent.
I also advise to do some sports. In some organized form with people. Maybe martial arts would be the best, since those offers self-defense techniques too. But the main thing is to get in shape, and keep healthy.