Some interesting simple facts about Copyright here:
https://web.law.duke.edu/cspd/public.../2012/faqs#q08
It seems that what can freely enter the public domain without breach of copyright, are works on which the copyright has expired. Then those works are freely available to all without "stealing" someone else's creative claim.
To be absolutely certain there is no disrespectful use of someone else's creative claim going on, research is needed to verify whether the copyright has expired or not.