It's a good topic, but not a big issue. I also noticed that a lot of clarifying is required when talking about speakers that are suppose to be mounted. Very few home audio bookshelves could be classified as monitors IMO. So I don't even think that the term monitor helps. Whenever I have "studio" people over at my place they all agree without exception that my KEF LS50's have far too much lows for a monitor. And these are being refer to as mini-monitors even by the manufacturer.
Monitor also implies a level of revealing, the name spurs from the process of monitoring what you do while in studio. You need some level of accuracy. Thus Sonus Faber stand mounts/bookshelves are not really monitors as they accentuate the presentation of music in a certain fashion. The philosophy of that company is that the speakers is an instrument (hence the names of the models; Guarneri (a luthier family), Amati (making violins), Serafino (a pupil of Amati, violin maker)...) I think only monitors should be called monitors. IMO none of the 3way stand mounts are really monitors and many of them are not being used in that way (KEF Reference 1 comes to mind).
There are two-way towers and three way bookshelves, so that won't do either, can't call them two-ways. Placing them on the shelf is generally to be avoided, back ported even more so, but front ported as well, it's because of the baffle and furniture resonance, not only the port, so...
I'd be OK with stand mounts and towers.