I don't know "what is normally expected" - but - certainly for my part - I often take pieces from various sources (again, of course being attentive to any copyright issues) - and I invariably give accreditation to the source I obtained it from.  That is only fair.   Very often, that can be something as simple as "Found on http://www.thesession.org" with an actual link to the item - or if it is more specific, naturally I'll credit the original composer (even if long passed-on, or even if out-of-copyright).   

I believe there is a "fair way" to work with copyrighted stuff - and I have approached some copyright owners (or their representatives) in the past - and generally there has been no problem at all.    I always explain (a) that my use of the piece is non-commercial, (b) it will (if I publish it on YouTube etc) be in the "Educational" category as distinct from the YT "Music" category (which, I already know attracts largely baseless and completely crass and stupid copyright claims by so-called AI algorithms) (c) promise to honour by accreditation the original composer or work.

If I "publish" something related to the piece other than a performance (indeed, such as the score I posted earlier today for Kelvin Grove) I will always add my own name - not for purposes of kudos or anything - simply so the score, once it is out-in-the-wild in the public domain, is traceable to some extent.

I understand your desire to be as honourable and fair as possible in these matters, and that is a Good Thing!