Is any of the information below in the public domain?
I think it will be hard to obtain more information. I found just one site which allegedly has in its database tenants and landlords - krwin.pl, however currently there's a "technical break", this company has a FB page, check here: facebook.com/mieszkanicznik/posts/452018424875573
The rank of their site, number of visitors, etc. shows that it isn't in good shape, so probably just the small percent of owners there, with skimpy and outdated information.
As far I know the landlords does not need to provide detailed information about their tenants anywhere, only the rental value - and even it may not cover the reality since owners in Poland have tendency to hide the real income to save on taxes.
Copy of Documentation covering the Legal Owner
There are some sites where you can download the copy of your property papers - "księga wieczysta" in Poland. You just need the number of it. There's also a possibility to obtain such number when you know the exact address of property, but you need to pay for such service: