The streetkids I recall from when I lived in Portland - before it became Hipster Heaven - fit the category you described; middle-class, suburban kids from various parts of Oregon and surrounding states. Runaways, mostly.
I understand the cops really can’t do much about it, unfortunately. I like downtown Portland, personally. You can easily walk from Pioneer Courthouse Square to Chinatown; it’s fairly compact. But to the streetkids all I can say is.....go home.
My only dealings with panhandlers are our smalltime “local color” kind. They’re very few, they’ve been around forever, they don’t approach people, they just take up their post they’ve had forever and hold up their signs once in a while. Older, white, usually bearded. After all these years, I don’t even have a clue as to where they sleep. They must have somewhere to be, I don’t recall that I’ve ever seen them out in bad weather.
Even though I don’t know if they’re “deserving” or not, I don’t mind giving them some money, because they don’t harrass people at all. It’s news if anything happens to one of them, or used to be.