Just a quick update: Roots! Yes, it took a long time to get this far, but if I had kept it in a warmer, more humid environment it would have gone much faster. Probably about half the time. Putting cuttings in a humidity tent isn't a bad idea, although you have to keep an eye on them to make sure it's not too humid and they get moldy.
But, we're halfway to getting the cutting in a pot, so that's good. This is what it looks like when they first start coming out. At this point you need to be very careful when you change the water, the roots are very delicate and can be broken off even by pouring water over them.
See part one in How to Propagate Ficus Benjamina.