Of the sampling instruments in the V Collection (CMI, Emulator II, Synclavier, etc.) which would be the recommended one for making a choir out of myself (i.e., a Me-llotron 
)? I’m thinking with respect to multisampling across the keyboard, crossfade and/or reverse looping.
Hi New numbers, interesting question.
This is a purely personal opinion, the easiest of the bunch is the Emulator II V, it’s incredibly easy and quick to create multi sample layers, splits etc and having the choice of a more modern converter, has a much more hi-fi sound.
The CMI V is more complex, but that complexity allows the user greater flexibility and control, again though the option of higher sample and bit rates compared to the original should the user want a more modern sound.
I’m not sure the Synclavier V would work in this situation as it doesn’t have sampling currently.
Historically the CMI hardware has been used on A LOT of recordings for things like choir, particularly back in the day.
Place the Mello-Tape plugin after it and either of them should sound great!
Something else to consider could be Arturia’s own Augmented Voices instrument? It allows all your requirements iirc and is quite simply superb, I’m a huge fan of it myself and seriously suggest you check it out if you’re not already familiar with it.
HTH!
The thing with Augmented Voices is that I don’t have a good way to get it to go where I want. I’d rather build something up from basic elements. I love Mellotron and plan to use it, but I also want something smoother and denser. The archetype I have in my head is Kurzweil K250 choir, like what Keith Emerson used on the ELPowell number “The Score.”
Hi
if you want a more complex sound i would go for the CMI, but if you need a more powerful sampler that allows you to do more things, it would be pigments or you could try using the vocoder.