I think we need Basic Housing in addition to Basic Income.
It was tried giving people housing. The problem is not doing that once - the problem is the ongoing process. Even in Africa the helpers switched to letting people pay for basic services instead of giving it to them for free, not because "capitalism", but because it turned out they didn't value free stuff and ruined or ignored it.
Similar with the homeless, and in addition a large part of them has mental issues! If you want to have ruined housing, sure, just give them free housing now. But a solution that involves an entire well-organized system that takes care of them and the housing is needed - and likely a very flexible individualized one. Some may need almost constant help, for others checking on them occasionally and giving nudges and support is enough. "Basic income" is not a solution for this problem. Most of those people on the street are very likely to gain next to zero benefit from (just) getting money.
Where can I read about these mixed results?
This seems like a bad idea. Any culture that contains something of value needs to absorb new members a little at a time. A culture or scene that tries to absorb many new members all at once is going to be damaged or at least significantly changed in the process.
So it would seem that scattered site housing is the new norm. Now, the problem is that it's harder for such residents to become part of the local community networks. (Often suburbia is distinctly isolating.)
Some social organization similar to a church would seem to be the idea method of providing the residents a social network.
Homeless are expensive as hell to have. They visit ERs instead of getting preventive care, not that they can afford either, they devalue property where they squat, they occupy emergency services like police when property owners complain, they spread disease, etc. etc. etc.
You can joke about giving people a home like it's just going to ruin the country, but we're already subsidizing these people with emergency services, jails, and police. Just giving them a home with some basic amenities both gives them the chance to actually contribute and at the same time, and basic income allows them to manage their own money, even if they aren't earning it, to give them some semblance of dignity.
And in almost every case studied, it's cheaper.
Don't get me wrong, there are plenty of homeless people who are like that and who really do just need a helping hand and some support for 6mo or a year and they're back to being productive members of society. I won't argue with this because it's absolutely true!
But there are also people who are homeless because of untreated mental illness, who "choose" to be homeless because they're too far out there to participate in traditional society. These folks (probably) need help, but just giving them a house and money for food isn't necessarily the answer.
And there are also folks who choose to be homeless. People who think society is really effed up and that they don't want to be a part of it. I've met folks like this and talked with them at length and they know full well what they're doing, why, and whatnot. They're not down on their luck and they don't have any kind of debilitating mental illness; they have very well founded reasons for rejecting society and you won't convince them otherwise. They obviously have different values than most, but that doesn't mean they're crazy or wrong. If you give them a house they'll probably just laugh at the "idiots" trash it, spend the money profligately and continue doing whatever makes them happy.
Pretending that you've got a one-size-fits-all solution to a problem is either incredibly naive or just downright intellectually dishonest. I'm not terribly interested in people peddling snake oil.
And as I said above, this doesn't solve the issue of mental illness but none of the current ones do either. I would argue the majority of homeless people are really just regular folks who have had a serious financial issue (the fastest route to the streets is the medical system) and giving them a leg up will not only get them off the street, but would likely get them productive again.
I'm not arguing that basic income is the silver bullet solution to our cities' problems. I'm arguing for what we spend on the patchwork crap system we have now, we could use much more effectively via basic income WHILE giving these people at least a passing sense of ownership of their own lives.
Without that I could simply assert that only 10% of homeless want to rejoin traditional society and you'd be powerless to refute me.