I'm not casting a vote, but way back when I was a newbie picked up the theme that 911 Targa was considered a coupe to be consistent with 1980s Ferraris (eg 348) which as normal coupes, targas (which we called coupes) and full convertibles. And the 911 had a full cabrio alternative from 1983, so that's where the lines had been drawn.

But with 911 Targa, it gets fuzzy as the first 2-3 years in 1960s had removable floppy rear window, which then became fixed glass 1969+. And then there was the 2001-05 Targa which had a new format (in effect a sunroof, plus an opening rear hatch).

Stags have H-top frame, accompanied by a removable hardtop. XJS SC is a weird one - with fixed rear side windows but floppy roof and rear window - if anything its format is most like an early 2CV, which can be (and probably has been) argued in several different directions.