Idk if it's even legal to evict for that but I've literally had zero issues.

More debt is available.But amateurs are playing in it.”

In your situation, the only thing that will likely matter is debt to income.  

Ground rent owners try to collect fees they are not entitled to like late fees, some legal fees, more than three years back etc.

Our realtor called his legal hotline and their opinion was we are good.  

And will I run into any legal trouble doing this?

This is what you can do , leverage that 500k windfall that you now have , look at getting 3 duplexes in the 550k range, put 25% down on each , a mortgage of approx. 400k won't be unmanageable , hopefully after debt servicing and operating expenses, your net should be about 1k on each , and if you can manage these yourself maybe you can maximize your return.

When one forecloses on a home with government tax liens, do they have recourse against the owner to try to recoup their debt up for a window of time?

Currently my wife and I are debt free including credit cards and saved up a decent chuck of change for retirement, mutual funds, stocks, and too much into CDs(lucky only one year at 3%).

It's also important to realize that HUD will do a very thorough underwriting of your qualifications to assume that debt.