First Issue: I can see how that could be annoying, but its a risk you take when you buy an apartment. A lot of that is due to very poor regulations re sound proofing which really should be addressed.
Second Issue: There is a huge green about ten yards from my apartment yet gangs of kids will congregate right underneath my sitting room, shouting and roaring and kicking footballs into the flower beds. I find that annoying, but have not ever made a complaint to the management company. Depending on the circumstances, however, I wouldn't necessarily judge someone for complaining. The kids could be causing damage, or climbing up on boundary walls, or making an unreasonable level of noise or some such, so its hard to judge in isolation.
Third issue: I can't see the problem there unless the ice cream van was coming around very early or very late with jingly music playing.