I found this fact sheet which seems to indicate it would be possible to evict the rent stabilised tenants so long as they haven't been living there for more than 15 years or are older than 62 or disabled: https://hcr.ny.gov/system/files/documents/2020/10/fact-sheet... 

Are there any other no documentation loans other than DSCR loans that I should look into?

However, if they are still considered a short-term guest under lodging rules, you may have more flexibility, though the specifics can depend on local regulations in Seattle.Since this can become a legal gray area, I recommend documenting all agreements, payments, and communication with the guest.

When I asked for identification documents, he claimed it was too many documents for an investment of "only" $10,000.

What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?

Very little documentation requirements, no income requirements, etc, just need to have on-time payment history for previous 12 months, and be lowering your interest rate at least .5%. 

If you do not want your name to show up anywhere on the closing documents, you would need to get a power of attorney to allow someone else to sign on your behalf. 

If you have a stable asset, predictable returns, and a lease structure that’s well-known and well-documented, a regular market valuation might make sense.

Additionally, your loan purchaser would supply the necessary documentation.

This is often achieved with written documentation, such as a formal ROW request from TxDOT or other correspondence indicating that condemnation proceedings were possible if no settlement was reached.