Interesting thoughts on the subject here. I have a much different take, especially for the 16 and 24 mainly because of their analog nature. I suppose I should say by way of background I'm an audio engineer here in Hollywood and have been for many, many years. I've set my official retirement date for Thanksgiving this year, good Lord willing and the creek don't rise. In that, I came from the days of tape. In that light, the obvious answer is of course you can record top to bottom on any of the three devices. We did it all the time in the tape days. If something needed to be mastered (which for television seldom is the case) we'd send it out to be mastered. It, of course, was a different approach to multitrack recording but in many ways, I think it was a much more creative approach, especially when it came to music production. That of course a discussion for another day.
I think as many have said the OP's question was answered early on in the thread but it's interesting to me that there are little or no thoughts on the analog side of the 16 and 24. Since I have my head in Pro Tools 10 hours a day I was looking for something outside of a DAW. Kinda a purposeful return to a non-visual recording environment. I also have continued my mantra of the irreplaceable "feel" of an analog console. For me, it simply can not be replicated in the digital domain. The same goes for analog eq. Again for me, the touch to ear to brain is intrinsically and palpable more organic. It's the connectivity that makes it feel different. So the 24 made all kind of sense for me and I gotta say the feel and sound of the 24 are just wonderful. In the end, I'll still use some Pro Tools most likely as a playback engine and some soft synths although I haven't fully mapped what signal flow I'll use. Still, the possibilities are pretty numerous.
Distilled the 16 and 24 are just wonderful recording solutions be it internal to the machine or not. I can't speak to the 12 but I'm guessing beside the smaller track count and digital mixer I'd guess it too would be a really capable machine.
Just my 2 cents :0