Different names for houses; legal, postal, informative and other

I am actively editing OSM around Helsinki area, and running into certain hair-splitting issues regarding naming and addressing of buildings - to be more specific, residential buildings, often apartment buildings (or "flats").

My question involves what should go or not go to "name" or "addr:housename" fields of a building. My current assumption is that if an address doesn't make sense or be necessary as a postal address or wouldn't be recognized by a local on the street, it shouldn't be in the "addr:housename" field. I also feel that "name" should have only names that make sense to the locals - that is, not names of obscure legal entities or such. Are my assumptions reasonable?

The background to this question is that some mappers in Finland seem to add names (full or abbreviated) of housing companies - which are legal entity names, as names of buildings. Housing companies operate one or multiple buildings, and if they operate multiple buildings, these buildings may often have more than one postal address. At the same time, the name of the company is, to my knowledge, never necessary to identify a specific building, either in postal address or in common speech location. In fact, post office would consider such addressing an unnecessary nuisance!

Other, considerably less common activity is to include a name for particularly (culturally, architecturally, or locally) significant apartment buildings in one of these fields. These names are often known (much better than legal company names) by the locals, but never part of a postal address.

So, my question is the following: should such names be included in "name" or "addr:housename" fields? If not, how they should be indicated? I understand that removing information from OSM metadata is counterproductive, but I'm unaware of the best field to put such details...