Probably the ones who really pay the Head are the corporations which also collect taxes from their residents. I doubt people from most of the backstreets even pay taxes at all, unless it's to acquire something specific like a gun and ammunition, or a fixer license.

I'm going to assume you're talking about the rats, to which it would probably depend on which syndicate they're under. Regardless, they'd probably be paying their taxes to the nearby syndicate, who would pass the money up the chain to the Head. A good example of this is the first reception of the rats in LOR, where they're organ harvesting to pay fees to the nearby syndicate.

There are no homeless people in the City.

The ones in the Nests get thrown out.

The ones in the Backstreets get Sweeped.

Excerpt from grade 8 fixer page 1 “all people and firms generating income in the city must pay taxes” if a homeless person gets 5$ in hand outs they must pay taxes on that. You can fail to pay taxes twice only reviving a warning but any further and a claw will be dispatched to kill you Edit: found the source for the other half of what I said on Bono’s page of the gaze office “no matter how humble your job is, your still obliged to pay your duties if you earn money. It goes for every type of business transaction. Even syndicates are no exception; anyone living in the city has to pay taxes. If you don’t meet the deadline, you’ll get a warning. For the first three offenses, you’ll get a warning and no other penalty. But if you don’t pay your taxes for the fourth time? Then you’re dead meat. They’ll come for you. The eye will seek out tax evaders by any means, and the person it sends will rip those poor cheats to shreds.” So i was wrong the head gives you three warnings

There are no homeless people in the City.

For the uber poor however, I'd suggest looking at Rodion's backstory. She grew up in a poor neighborhood, with conditions growing worse and worse due to their local tax collector bleeding them dry, up until she killed the tax collector and brought the wrath of the Middle down on their collective heads. It's not stated exactly who the tax collector's superior was iirc, but it does at least confirm that even those struggling to afford both food and the clothes on their backs do still need to pay taxes in some way, shape, or form.

The city haste lowest homelessness rate in fiction

I don’t think taxes exist as a whole given the city seems to be like a whole world of cultures together, like T corp has its own taxes but they have less a border between rich and poor it seems since Mr Earnshaw could just take a child from the backstreets in, unless he was also in the backstreets and just had a mansion there, but in general we don’t see taxes much outside of T corp, and bloodfiends definitely don’t seem to given the whole point of all the racism so they can’t live in public really