Is there a word for the other sort of "man-beautiful"? Not ikemen, but...well, think Kelso (or Ashton Kutcher in general) as a live-action version of man-pretty (Bishounen) and Angel as a live-action version of man-beautiful (_____). Is that just typically described as Bidanshi/Biseinen (I would reluctantly guess which would depend on age), or is it some other thing? Is it just "beautiful [in reference to a male]"? I was in a discussion a while back, and was unable to find the sort of term to explain what I wanted to mean when talking about a character who seemed, in my mind, bishounen without any of the feminine visual connotations of "pretty" (i.e., not actually bishounen).
If they're handsome rather than pretty, then it's Mr. Fanservice, or Tall, Dark and Handsome (David Boreanez, or Ashton Kutcher). Bishonen need to have delicate and feminine features, high cheekbones, pointed chins, clear complexion, not really broad shouldered or overly muscular.
Does Sephiroth pop in your head when you hear the word bishonen? Guess what? He's too old and too muscular to actually be one.
How can someone be "too old" to be bishie? It's all about appearance.
Not to mention, the trope page even says to list both bishonen and biseinen...
No, no. Bishonen refers to beautiful young men. Sephiroth would be biseinen or beautiful older man.