Besides getting mail from some of the others you mentioned to sell to, I’ve only had experience using Upnest as a seller:I used it in 2019, when I found myself without a local agent I could trust in a remote market where I suddenly decided to sell.

What if a large judgment or lien suddenly comes into play?

You introduced the concept of a Lender giving out as much as 80% market value, but I've seen other posts/threads where, even if the Lender says they'll lend 80%, their appraisal suddenly gets more conservative, so the borrower may end up with about the same as what another Lender calls 70% LTV anyway (and with worse terms to boot)!

If you're buying it for 225 and planning to put zero work into it, then how is it suddenly worth 275?

Some of my money, some financing, father is the GC (which makes the full-gut across the continent not as scary a risk as it sounds).Spent two months wondering why no one would take our money for a house, once we figured out what worked, we suddenly realized we needed to think a little bigger (was doing it all my cash, now I'm good with some leverage).I've got a nice w2 that I'd love to dump for half the salary, if I could generate it, but I'm thinking that might be many years from now.Anyways, I'm heading to Atlanta Wednesday morning through Sunday morning. 

I've seen Private Investors pool money where their friends cash out of IRAs, 401k, Annuities, incurring penalties to fund loans for borrowers who suddenly go MIA on the day of loan funding!

Overall, if you've found a good tenant, keep them as long as you're able to, and no need to worry about a sudden switch in behavior! 

The second something bad happens in life or challenging and people want to check out or say look what happened to me that is when people give themselves permission to fail.Life is tough,very tough but we all need to keep moving forward.When I was 16 years old I lost my dad to a car wreck suddenly, my best friends dad to cancer, and my grandmother all in the same year.

You make it sound as though they did this suddenly.

If you suddenly inject close to $1T into the US economy and it is done efficiently (not by the government) this will have a huge impact on US growth.