While most of these things are possible, FAIT's spawning UI is already more cramped and confusing than I'd prefer it to be, so something like this is better suited to being its own mod.
That said, all of these things save the configurable distance are more or less doable via FAIT's advanced spawn config, though you'd have to set it up to your preference on each individual map.
Thanks for the response, Fin. I may have posted too soon. Perhaps it was the changes I made in the Advanced spawn config, but the first time I tried implementing the changes, it spawned everyone in the same zone. This second time around, I simply used your "Immediate" spawn, even distribution, and zone limit parameters and that has done the trick. I'm still tweaking the maximum number, to try and reduce the strain on my PC (I start losing some FPS when everyone is on the map), but it's working great otherwise.