Please put a location and or zone next to your name so we can help better, as some advise depends upon your location. A North facing window is not enough light for a tree, they need a South facing window to get through the winter. A West window will keep them alive but it's still not enough light. You may have to add lighting to give the plant enough. The white on the stems could be latex sap or mealy bugs, it's hard to tell. The spots look like oedema ( when the plant has too much water in it's stems and leaves and it gets too cold causing cells to burst) Some of the leaves look way too dry also. It could also be accumulated salts causing the brown leaf tips. The next time you water do a full flush. You will probably need help to get it to the shower but give it a really good soak. Do not let the water get too cold. When it's done draining, tilt the pot a few times then move it back. (hopefully to better lighting)

Just keep eye on the healthy leaves. If other leaves stay healthy in 2 or 3 days, then nothing to worry. If the symptoms spread further, maybe soil nutrients deficiency is the cause. No need to cut off any leaves since they still able to do photosynthesis, but if you think remove unhealthy leaves will make you feel better, then go ahead. Seems that you have enough healthy leaves to support plant growth.

11/1/17 update: it’s gotten much worse. The pale splotching has suddenly increased in frequency and spread. I’m noticing splotches on more leaves, and overnight they will turn completely. Some of the branches look gray too: Did I give it too much light too quickly after the transplant? Some of the fine roots came off during cleaning so maybe it has too many leaves in comparison to the roots? Also, the breeze has started to turn cold. It’s still 72 degrees F but the breeze in the house is definitely cool instead of warm now. Is it too cold in front of an open window? I have a spot near my other plants where the light is bright, but it’s essentially where it used to be (on the catwalk) just with more air circulation. The FLF I transplanted in gritty at the same time is looking very strong but hasn’t had new growth after its repot in May. It’s on the same wall just on the other side of the room. The brown spots were from previous root rot. They’re all about 10 feet from a wall of East-facing windows: Here’s the soil now: About 4 months after receiving, when I started noticing the hypo-pigmentation: Right after transplant: Currently: Pale splotching/bleaching used to just be a few leaves at a time but now they’re in handfuls. So far, loss has been all lower leaves but the top is drooping significantly. Too much light too soon? Too cold with an open window even if it’s around 70 degrees F outside? Just normal stress response to changes? It’s been about a week. All thoughts appreciated!

Do a search in the “houseplants” section. There are hundreds of posts about this tree. Also, these two links will greatly help you. http://forums2.gardenweb.com/discussions/1476078/ficus-trees-in-containers-iv?n=223 http://forums2.gardenweb.com/discussions/2842847/container-soils-water-movement-and-retention?n=8